Publication Year: 2014 Title: First Discovery of Topazolite in Mexico Abstract: Garnet occurs in a wide variety of colors according to composition: pyrope and almandine (typically red), spessartite (brownish to orange), grossular (brown, yellow, and green), andradite (brown to black), and uvarovite (bright green). The three varieties of andradite are melanite, topazolite, and demantoid. Topazolite, a name that has been criticized as too similar to that of the gem species topaz, is a greenish yellow to yellow-brown andradite. According to some studies (e.g., C.M. Stockton and D.V. Manson “Gem andradite garnets,” Winter 1983 G&G, pp. 202–208), it rarely occurs in crystals large enough to be faceted.

In January 2014, during mineralogical investigations of Mexican garnet, we made the first reported discovery of fine topazolite crystals in Mexico. These yellow to yellow-brown crystals, measuring 1.5–2.5 cm, are hosted by the Las Vigas skarn deposits (the Cerro de la Concordia mine in Las Vigas de Ramirez municipality and the Piedra Parada mine in Tatatila municipality). The deposits are located in Veracruz State, about 50 km southeast of the town of Valle de Veracruz.

The garnet composition was determined by electron microprobe, using a 41-point analysis and standard conditions of 20 kV, 20 mA, and 1 µm beam size on a JEOL JSM-35c microprobe. We chose a euhedral, relatively homogeneous crystal about 1 cm in diameter from the specimen shown in figure 1. Measurement time was 30 seconds on the peak center. The standards used were MgO for Mg, Al2O3 for Al, jadeite for Si, wollastonite for Ca, and elemental Fe and Mn. The electron microprobe analyses showed little compositional variation or zoning. We calculated the structural formula on the basis of 12 oxygen atoms, with the assumption of all iron as ferric. The approximate composition averaged (Ca2.86Mg0.06Mn0.02)2.94(Al1.20Fe3+0.72)1.92Si3.03Ti0.05O12, which may be expressed as Gr60.50And36.70Py2.80.

Figure 1. This topazolite specimen is from a recent discovery in the Mexican state of Veracruz. Photo by Cristobal Castillo.
UV-visible spectroscopy showed absorption bands at 375, 416, 442, 497, and 584 nm, which can be assigned to the spin-forbidden crystal-field transition of Fe3+ substituted on the octahedral Al3+ site of the garnet structure. The correlated set of these bands also show a pattern close to that characteristic of a d5 trivalent ion in octahedral oxygen coordination. The Mössbauer spectra were characterized by a sharp, slightly asymmetric ferrous doublet. The UV-visible and Mössbauer spectra are comparable to those reported for some garnets in previous reports (A.S. Marfunin, Ed., Advanced Mineralogy, Vol. 2, Springer-Verlag, Berlin, 1995, pp. 74–75, 114).

The three samples of rough topazolite (measuring 1.0–1.5 cm in longest dimension) gave the following properties: yellow-brown color; isotropic and weakly anisotropic; weak strain birefringence; RI—nα = 1.84–1.89; hydrostatic SG—3.75–3.85; and fluorescence—inert to both long- and short-wave UV radiation.

This Mexican topazolite deposit has not been mined, and in the absence of detailed geological, mineralogical, and gemological study, no estimate of the reserves is available. For now, there are no specimens or fashioned material from Las Vigas in the Mexican lapidary market. @chapter:13


Publication Year: 1994 Title: Ruby and Sapphire from the Southern Ural Mountains, Russia Abstract: Primary occurrences of ruby, pink sapphire, sapphires of other colors, and spinel have been found in marbles in the Ural Mountains. This article describes one occurrence, at Kootchinskoye, in the southern Urals, as a model for others in the Ural Mountains. Study of Kootchinskoye also gives some guidelines for predicting other ruby deposits. Although at present, there is no commercial production in this area, it appears to have significant potential. @chapter:0


Publication Year: 2004 Title: Lab-Grown Colored Diamonds from Chatham Created Gems Abstract: Synthetic colored diamonds (yellow, blue, green, and pink) from a new source in Asia are now being sold by Chatham Created Gems of San Francisco, California. Some of this new material displays hues and weaker saturations that more closely resemble natural diamonds than most of the synthetic diamonds we have encountered previously, which typically had very intense colors. These as-grown and treated type I and type II synthetic diamonds, produced by a high pressure/high temperature process, have many distinctive visual and spectroscopic features that serve to separate them from natural diamonds. These include geometric patterns of color zoning and luminescence, metallic inclusions, and bands seen in the visible and photoluminescence spectra. @chapter:11


Publication Year: 1997 Title: Spring 1997 G&G Lab Notes Abstract: Two Noteworthy Diamonds from the Americas
Diamond Damaged from Wear
Identifying Filled Fractures in Diamond
Imitation Diamond
Hornbill "Ivory"
Mogul Talismans: Spinel, Sapphire and Aquamarine Beads
Opal with True Chatoyancy
Quartz with Cat's-Eye Effect Caused by Large Rutile Needles

To view the full section, download the PDF above. @chapter:23


Publication Year: 2008 Title: Color Grading “D-to-Z” Diamonds at the GIA Laboratory Abstract: Since its introduction in the early 1950s, GIA’s D-to-Z scale has been used to color grade the overwhelming majority of colorless to light yellow gem-quality polished diamonds on which laboratory reports have been issued. While the use of these letter designations for diamond color grades is now virtually universal in the gem and jewelry industry, the use of GIA color grading standards and procedures is not. This article discusses the history and ongoing development of this grading system, and explains how the GIA Laboratory applies it. Important aspects of this system include a specific color grading methodology for judging the absence of color in diamonds, a standard illumination and viewing environment, and the use of color reference diamonds (“master stones”) for the visual comparison of color. @chapter:31


Publication Year: - Title: A Visit to the Kagem Open-pit Emerald Mine in Zambia Abstract: Compared to other colored gemstone operations, the pit at the Kagem emerald mine is quite massive. Blasting is used to remove the topsoil and waste rock that cover the emerald-bearing ore. Photo by Vincent Pardieu/GIA.

	Introduction
Today, strong and ever-expanding demand for colored gemstones has made the sourcing of these fine gems one of the industry’s biggest challenges. The Gemfields operation at Kagem is a model for possible future colored gemstone mining operations as well as for participation in the mine-to-market supply chain. The operation encompasses processing, sorting, and grading, all intricately tied to Gemfields’ marketing campaigns and auction systems. Gemfields offers expertise in capital investment, mining, marketing, best business practices, government and local partnerships, and sustainability—a complete strategy that carries all the way to its auctions.

The GIA team was led by Vincent Pardieu, GIA Senior Manager of Field Gemology, based in Bangkok. Accompanying him were Andrew Lucas, Manager of Field Gemology in Carlsbad; Tao Hsu, Technical Editor of Gems & Gemology in Carlsbad; videographer Didier Gruel; and expedition guest Stanislas Detroyat. This was a return visit for both Vincent and Didier—the third for Vincent since 2011 and the second for Didier, who first visited along with Vincent in 2012. For the others, it was their first opportunity to observe the mine and its operation, which they had been following from afar for a number of years.

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	The GIA Team
The team’s main objectives were to collect new on-site reference samples for the GIA Lab as well as to witness, document, and report on the evolution of the mining activity. The team was able to retrieve many pieces of emerald rough directly from the host rock to use for new reference samples, and to study the production at the sorting house. They spent several days observing operations at the mine and interviewing Gemfields’ management and staff, gaining a deep understanding of the mining operation and how it fits into Gemfields’ goals of revolutionizing the colored stone industry.

	Tao Hsu collected one of the most impressive additions to the GIA emerald reference
	database from Kagem’s Chama pit. Photo by Vincent Pardieu/GIA.

	The Country of Zambia
Zambia is a landlocked country in southern Africa, surrounded by the Democratic Republic of the Congo, Tanzania, Mozambique, Zimbabwe, Botswana, Malawi, and Angola. Its total area is 752,618 square kilometers. The climate is mostly tropical, with a rainy season from October to April that brings substantial amounts of rainfall. The terrain is mostly high plateau with some hills and mountains. While the country is landlocked, the Zambezi River forms a natural border with Zimbabwe and allows for transportation of materials by boat. The river has also given rise to a major tourist industry at Victoria Falls for both Zambia and Zimbabwe. Lake Kariba, the world’s largest reservoir by volume, also borders Zambia and Zimbabwe.

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	Victoria Falls and the Zambezi River
Zambia’s population consists of an estimated 14.5 million people, encompassing several different ethnic groups. The largest groups are the Bemba and Tonga. English is the official language because it’s a former British colony, but over 70 languages, mostly dialects, are spoken in the country. Most are related to the Bantu family of languages.

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	Zambezi River Wildlife
Growth of the Zambian economy was strong between 2005 and 2013, averaging over six percent a year. Traditionally, since its discovery in 1895, copper has been the country’s main source of revenue. The privatization of government-controlled copper mines in the 1990s and the surge in copper demand and prices over the last decade have made Zambia’s copper industry profitable. Over 43 percent of Zambia’s copper exports go to China, a major buyer. The presence of a strong mining culture around Kitwe, the capital of the Copperbelt Province where the Kafubu emerald mining area is located, had a direct impact on the establishment and success of emerald mining in Zambia. Zambia is known to produce several other types of gemstones, including amethyst, beryl, and garnets, but emeralds are Zambia’s most economically important gemstone export.

Local employees are hired to work at Kagem’s washing plant. Photo by Stanislas Detroyat.

	History of Zambian Emerald Discoveries
Gem-quality emeralds are found in north-central Zambia, near the Kafubu River and about 45 km southwest of Kitwe, a town considered the hub of the famous Zambian Copperbelt Province. It is also home for numerous workers involved in the nearby emerald mine. Early European copper prospectors like William Collier had to wait until the 1920s, when a technical breakthrough made it profitable to mine their discoveries.

The first discovery of beryl in the Kafubu area was made in 1928 by Dick and Baker, geologists from the Rhodesian Congo Border Concession Company. They completed their investigation in 1931, concluding that the deposit had little economic significance. This decision was probably due to the company’s main interest in copper at the time.

	The Kafubu area is well known as one of the largest emerald-producing areas in the world.
Although the initial prospects for beryl production were not overly encouraging, further exploration was undertaken by the Rhokana Company in the 1940s and by Rio Tinto Mineral Search of Africa in the 1950s. In 1966, the claim was passed on to a small private company, Miku Enterprises Ltd. The rights passed again to a government-owned company, Mindeco Ltd., in 1971. Zambia’s Geological Survey Department then mapped the Miku area and located the deposit. They published the results in 1972 and 1973.

These works, plus discoveries made by some local miners of deposits called Kamakanga, Pirala, Fibolele, and Fwaya-fwaya, led to the rapid expansion of emerald exploration and production in the 1970s. Huge economic potential and extensive illegal mining soon forced the government to relocate the local population and form a “restricted zone” called the Ndola Rural Emerald Restricted Area (NRERA).

	Ndola Rural Emerald Restricted Area (NRERA) is located within the Kafubu area.
	Kagem mine is on the north side of the Kafubu River. Reproduced courtesy Gemfields.
The establishment of this restricted area allowed only government-authorized mining by large-scale companies and small-scale local miners. In 1980, government-controlled Reserved Minerals Corp. took over all rights and delineated a mineralization area of about 170 square kilometers. The production from this area has since increased significantly. In the same year, Kagem Mining Ltd., 55 percent of which was owned by the Zambian government, was authorized to explore and mine in the Kafubu area. Since 1984, the mine has consistently produced some of the finest Zambian emeralds. Kagem properties are located on the north side of the Kafubu River. Hundreds of prospecting claims are also being worked outside of Kagem’s concession.

In 2004, the British public-listed Gemfields Resources PLC started systematic exploration near the Pirala mine, south of the Ndola River, and made some important discoveries. Mining began in 2005. By 2007, Gemfields had already acquired 100 percent ownership of two mines in the area. In June 2008, Gemfields formed a collaboration with the Zambian government, establishing a 75/25 ownership split of the Kagem emerald mine.

In 2008, before Gemfields took control, the floor of the big pit at Kagem had almost no minable ore. By the following year, its yield had increased greatly. Photo courtesy Gemfields.
When Gemfields acquired control of the mine in 2008, the main open pit was yielding almost no minable ore. The company invested huge amounts of capital and used its know-how to change the conditions there. By the time the fiscal year ended on June 30, 2009, Kagem had produced 27.6 million carats of emerald at an operating cost of about 40 cents per carat (data from Gemfields PLC operational updates, August, 2009). From 2009 to the present, Gemfields has held nine high-quality and six low-quality emerald rough auctions.

The company also collaborates with Collector’s Edge Minerals, Inc., a Colorado company, to develop emerald specimens for marketing to mineral collectors. The first emerald specimens produced by Kagem debuted at the 2009 Denver Gem and Mineral Show. Kagem is now considered the world’s single largest emerald mine.

The Kagem mine yields fine emerald rough like this crystal in matrix. Photo by Stanislas Detroyat.
The key to Gemfields’ Kagem success story seems to be the company’s knowledge regarding mining primary deposits, raising capital, financial planning, and exploration. They have taken advantage of the already existing mechanized mining infrastructure in the Copperbelt Province, and also used their well-organized auction system to support their ability to obtain the best possible prices for their production.

	Regional and Local Geology
The Kafubu area is located geologically at the center of the transcontinental Pan-African belts in central-southern Africa. This is a critical area that separates the Congo craton to the north and the Kalahari to the south. In central Zambia, the Mesoproterozoic units are crosscut by the Pan-African Lufilian Arc and the Zambezi Belt. The crustal thickening and its intrusions are thought to be related to two corresponding orogenic events: the Mesoproterozoic (ca. 1300-1000 Ma [million years ago]) lrumde orogeny and the Late Proterozoic to Cambrian (ca. 750-500 Ma) Lufilian orogeny (John et al., 2004).

	The Kafubu area is located in central Africa, at a critical intersection of the continent’s
	Pan-African belts. Map reproduced from John et al., 2004.
Emeralds from Zambia can be of the same quality as their counterparts from other world-famous sources like Colombia, but they formed in quite different rock types. Unlike Colombian emeralds, emeralds from Zambia are rich in iron and have higher refractive index and specific gravity (Zwaan et.al., 2005). Emerald deposits in the Kafubu area occur within rocks of the Mesoproterozoic Muva Supergroup (1800-1100 Ma), composed of both metavolcanic and metasedimentary rocks.

In the Kagem mine area, the Muva Supergroup overlays a basement complex that’s about 1,800 to 2,050 million years old. It consists of talc-magnetite schist, amphibolite, and quartz-mica schist, layered from the bottom to the top of the pit. These lithounits lie on top of mica schist and strike generally along ENE-WSW to NE-SW, with a low to moderate southerly dip. Pan-African pegmatites intrude into the entire unit. The pegmatites are believed to be related to neighboring granitic rocks that originated or were rejuvenated at the beginning of a global tectonic event.

	All the Kagem emerald pits are located in the Mesoproterozoic Muva Supergroup. Besides
	Kagem, there are many other emerald mining operations with similar geology in this area.
	Map from Zwaan et al., 2005.
When the beryllium-rich magma and the fluid derived from it interacted with the surrounding chromium-and vanadium-rich host rock, ionic exchange occurred in the reaction zone between them. Within this reaction zone, the chemical components of chromium, vanadium, and beryllium mixed together under the right pressure and temperature conditions (400-600 MPa and ~590-630 °C) and chemical environment. These conditions led to the mineralization of both common beryl and emerald.

The metasomatic reaction between the host rock and the pegmatite formed both common beryl and gem emeralds. Reproduced courtesy Gemfields.
There are two pegmatite phases in the mining pits inside the Kagem mine. Older, shallowly dipping (an average of about 16 degrees) quartz-tourmaline veins were crosscut by younger quartz-feldspar bodies. There are two schools of thought regarding the age relationship between the quartz-tourmaline veins and the pegmatites. Some believe that the emplacement of the quartz-tourmaline veins occurred toward the end phase of the pegmatite intrusion and others believe that they are older than the pegmatites. Both intrude into the talc-magnetite schist, whose parent rock, believed to be komatiite, formed during earlier orogenic events. Komatiite is a type of ultramafic volcanic rock that formed during the early history of the Earth (mainly between the Archean and Lower Proterozoic periods). It has extremely high magnesium content.

Talc-magnetite schist provided emerald’s key element of chromium, while the pegmatites provided the beryllium. Based on previous research, it’s known that magnetite comprises up to about 4 percent of the total volume in the talc-magnetite schist and that the average chromium concentration in the magnetite is about 4-7 percent by weight.

Emeralds are found in both the reaction zones between the talc-magnetite schist and the pegmatites and in the quartz-tourmaline veins. The reaction zones are usually altered to phologopite-biotite-tourmaline aggregates, which are soft and easily disintegrated. The softness also provides an ideal environment for preservation of the emeralds. According to Kagem’s Senior Geologist, Robert Gessner, the best emeralds are usually found in the quartz-tourmaline veins. Kagem processes enormous amounts of ore annually, but only a tiny percentage produced from the emerald-bearing quartz veins is suitable as mineral specimens for collectors.

Robert Gessner, Kagem’s Senior Geologist, holds a piece of phologopite-biotite-tourmaline aggregate from the reaction zone. The rock is very soft and easy to break, and also provides ideal protection for the emerald crystal. Photo by Andrew Lucas/GIA.
Typical layering from the bottom to the top of an open-pit operation starts with the oldest basement complex, consisting of gneisses, amphibolites, and kyanite-bearing schists (~2050-1800 Ma). It is followed by the talc-magnetite schist, with ages between 1800 and 1100 Ma; amphibolite; reddish brown quartz-mica schist; and topsoil about 3 to 5 meters thick. The talc-magnetite schist, amphibolite, and quartz-mica schist all belong to the Mesoproterozoic Muva Supergroup. Quartz-feldspar and quartz-tourmaline veins intrude into all of these units.

This is a general view of a cross-section of the big pit. The main rock units include pegmatite, mica schist, amphibolite, and talc-magnetite schist. Emerald is often found in the reaction zone between the pegmatite and the schist. Photo courtesy Gemfields.
In the Chama pit, the talc-magnetite bodies strike east to west while the pegmatites trend roughly north to south. The pegmatites trend toward the west due to some later deforming events. However, local variations are almost unavoidable. Shear zones, which are zones where deformation is notably higher than in the surrounding rock, and folds, are very common. Geologists guide the operation based on their onsite observations. There are some places where emeralds are more concentrated. When a quartz-tourmaline vein and a quartz-feldspar vein intersect each other in the talc-magnetite schist, this forms a “tri-junction.” The pressure and temperature conditions and an ample supply of the necessary chemical components create a nice environment for emeralds to form.

When a quartz-tourmaline vein and a quartz-feldspar vein intersect each other in the talc-magnetite schist, a “tri-junction” forms. The appearance of two pegmatite shoots makes this tri-junction ideal for the exchange of emerald-forming elements. Photo by Andrew Lucas/GIA.
There are many talc-magnetite schist belts in the NRERA. The most historically significant and productive of them is the Pirala Fwaya-Fwaya belt, which extends for 8.5 kilometers in an east-west direction. Two and a half kilometers of this belt lie within the Kagem license, which extends from the Kafubu River to Libwente. The largest operation, Kagem’s Chama pit, is located at the east-central part of the belt.

Core drilling data proved a strike length of 2500 meters at Chama. The current open pit has dimensions of about 1000 meters by 600 meters and reaches a depth of up to 120 meters. Besides Kagem, there are at least five other mechanized mining operations and hundreds of active artisanal miners working in the area. The recent appearance of Chinese investors, previously involved in copper mining, is becoming more noticeable in multiple emerald mining operations.

	The Mine
Zambia’s Kagem mine is located in the southern part of the Copperbelt Province, in the emerald mining area south of Kitwe. The first thing that catches your attention is its scale. Over a kilometer in length, it is enormous compared to most colored gemstone mining operations. The size of the pit is directly related to the geology, as the mining targets the phlogopite-biotite contact zone between the pegmatites and the talc-magnetite schist where the emeralds are found. The size of the pit is dictated by the need to access this contact zone.

	The Kagem emerald mine lies in the Kafubu emerald mining area. Reproduced
	courtesy Gemfields.
The mine had been operating under other management for 19 years when Gemfields came to Kagem six years ago. The operating Chama pit had a poorly excavated 60-meter highwall, covered with waste soil. The previous operation had targeted only outcropped contact zones, without removing waste or overburden. Miners were lowered into contact zones in excavator buckets.

Gemfields spent one year cleaning out the pit and removing the pegmatite and talc-magnetite schist to expose the emerald-bearing contact zones. Today, the highwall is 120 meters high, with professionally excavated benches of 10 meters each. Benches and berms provide a safe, stable highwall for mining operations. They removed a tremendous amount of rock, and the open pit is now 45 meters deeper, with a total depth of 105 meters.

Kagem increased the total depth of the Chama pit from 60 meters to 105 meters. The pit’s length is roughly 1 km. Photo by Vincent Pardieu/GIA.

	Open-pit Mining Methodology
Kagem is primarily an open-pit mine. One advantage of open-pit mining is that it makes every carat of emerald accessible. An underground operation requires leaving walls, ceilings, and pillars intact for shafts and tunnels, limiting or eliminating access to the emeralds in those areas.

Gemfields uses a strip-and-fill method to mine its deposits. A pushback occurs when they move the highwall of the pit farther back to continue exploiting the deposit. Since Gemfields took over, there have been four highwall pushbacks, with the fourth one now in progress. Ore production is currently taking place at the third pushback. The first three pushbacks were all 50 meters, and the fourth one is 75 meters. At the fourth pushback, three years of highwall waste stripping will provide enough ore for five years of mining. Based on resources estimated to be in excess of 1 billion carats, the mine is expected to have another 25 years of life.

An excavator strips the highwall of the pit and loads the material into the truck. The truck transports the material to its processing destination. Photo by Vincent Pardieu/GIA.
Gemfields uses a contractor to remove the mica schist/amphibolite waste during the highwall stripping process. The contractor removes about a half million tons a month, working 24 hours a day and seven days a week. Using its own operating fleet, Gemfields mines the potential emerald-bearing contact zones, which can vary from a couple of centimeters to a couple of meters. Exposed emerald crystals are removed by hand tools and sent to the sorting plant. The materials in the rest of the contact zone are loaded by the excavator into trucks and taken to the processing plant for recovery of any emeralds not seen and removed by hand tools.

	Miners chisel the reaction zone rock to recover any emeralds it might contain. The chiseling
	and recovery are supervised by geologists and security staff. Photo by Vincent Pardieu/GIA.
Daytime operations are reserved for production mining by Gemfields personnel of the phlogopite-magnetite schist contact zones. Daylight provides the best visibility for recovering emeralds by hand chiseling, and for security to minimize the possibility of theft. The strip-and-fill operation takes place before and after production mining.

The hard-rock overburden stripped away by the contractor and in-house fleet is used to fill in an area located at the opposite end of the pit that is already mined and exhausted—an area called the footwall. This helps to reduce the overall size of the pit and to keep environmental liability costs down. It also makes sound economic sense in that the shorter the distance they have to transport material, the lower the overall cost of mining per ton. The key to the strip-and-fill method is to find the right balance between waste rock removal and contact zone mining for the optimum continuing recovery of emerald.

The pit at Kagem is enormous. Its pushback wall is on the left, with benches. The footwall opposite that is filled in as new mining takes place. Photo by Andrew Lucas/GIA.
To protect the emeralds, Gemfields blasts the talc-magnetite schist and the pegmatite separately, but never the contact zones. The excavator then removes enough material to expose the contact zone for the recovery crew, called chiselmen. After excavators open up a contact zone, the team of chiselmen comes in with security personnel and chisels materials in the contact zone to recover the emeralds. Chiselmen have years of experience to guide them during this entirely hand-powered operation.

Blasting is an essential part of the mining operation. It begins the process of creating pushbacks to allow chiseling and ore removal. Photo by Andrew Lucas/GIA.
Security and supervisory staff are always present during hand-chiseling of the exposed contact zone to recover the emeralds. This not only helps to secure the emeralds from theft but also helps to provide complete transparency of recovery. Any production found goes into a locked production box. The geology staff and security staff have keys to the boxes, which are secured and transported to the sorting house. Cobbing to remove schist from the emerald crystals is done at the sorting house and not at the pit. The mining process is designed to handle as much rock as possible while also taking care to not damage any crystals and to ensure the security of the recovered emerald crystals.

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	Chiseling for Treasure
Kagem monitors every piece of equipment for operational efficiency and surveys every ton of rock. Material from every contact zone is documented by location and production, and that documentation stays with it through final sorting of the emerald it yields. Every pushback and every sector of the pit is documented for amount of waste rock, number of contact zones, and production level, including quantity and quality of emerald. This information helps them project production for the next pushback.

Gemfields’ five-year plan for the future involves removing the waste rock from the fourth pushback and mining the exposed contact zones. While colored stone mining recovery rates and qualities cannot be precisely projected, historical data can be used to estimate future production. The current mining and pushback plans were formulated in 2013.

To allow for the possibility of future additional exploration in key target areas, Gemfields doesn’t re-fill all of its mined pits. Instead, they leave them open and allow water to accumulate in them. To offset the carbon footprint, the mine’s waste areas are rehabilitated by covering them with soil and planting trees. The company’s goal is to practice sound, profitable mining that leaves the environment in a better state than when they found it. When Gemfields took over the mine six years ago, it had an environmental liability of more than $5 million. Today, that environmental liability has been brought down to around US$350,000.

Mining operations in Zambia have to contend with the wet conditions in the area. Although our visit was during the dry season, there was still water in the pit, due primarily to the presence of natural groundwater. During the rainy season, substantial rainfall fills areas of the pit with water and raises the groundwater level. Gemfields has planned the pit so the excessive water that accumulates during the rainy season will pool in the deepest areas, which are not being mined, while mining is going on in the more high-lying areas. Even so, Gemfields still uses large amounts of diesel fuel to operate the pumps that remove the water from the pits during the rainy season. The mud and constant rains make mining more difficult, but it can still be continued throughout the year. Smaller mining operations simply cannot afford the equipment needed to remove the water, so they often stop mining during the November to March rainy season.

There is always some water from rain or groundwater seepage in the pit. Photo by Andrew Lucas/GIA.
At Kagem, the geology department is intimately involved in planning and mine operation. As with Gemfields’ Montepuez ruby mine in Mozambique, they embrace the philosophy that geology dictates the mining. Another department is responsible for security and safety, and ensuring the highwalls are at the proper angles to be safe and secure.

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	Strip-and-fill Mining

	Underground Exploration Pilot Project
For more than five years, Gemfields has been experimenting with a pilot underground operation. Its scale is not suitable for production, but they have learned a lot about the feasibility of an underground mine. Considering the extent of the underground ore that Gemfields now knows to exist, they will continue to pursue this project. Gemfields will increase the scale of underground operations as they learn more and get a better sense of its potential. The underground mining pilot project is being used along with the drilling project to better understand the entire deposit and how to successfully mine it.

	To reach the working galleries, the underground mine starts with stairs leading to a
	decline ramp. Photo by Andrew Lucas/GIA.
Historically, Zambian emerald mining has always been done by the open-pit method. This is due partly to a number of local challenges to going underground, such as the amount of water in the area. While we were in the pilot underground mine, we observed that water was constantly dripping from the tunnel walls. The underground water level is generally high, but it is even higher during the rainy season. Thus far, Gemfields has been able to handle the water in the experimental mine.

The pilot project looks at a number of unknown factors when deciding on techniques to be used for underground mining, including ventilation, rock supports, water seepage, and geology. The project started with a decline tunnel and within 5 meters they were into the talc-magnetite schist.

We went 30 meters down the current decline shaft and through horizontal tunnels to where the quartz-tourmaline and quartz-feldspar pegmatites vertically intersect the talc-magnetite schist, and the emerald-forming contact or reaction zones are seen. Over the last five and a half years, Gemfields has developed over 950 meters of underground mining, consisting of narrow tunnels and crosscuts. Every square meter of the underground operation has been surveyed and roof-bolted for safety. All the tons of rock removed were catalogued as part of the learning phase for future potential underground production.

Kagem Senior Geologist Robert Gessner explains the geology of Zambian emerald by showing formation zones in the underground mine. Photo by Vincent Pardieu/GIA.
Currently, Gemfields is using a rope and pulley system to haul the material out of the tunnels in bags. This system is cost effective but labor intensive. It has worked fine for the pilot learning project but would be a bottleneck if used for full commercial production. Over five and a half years, all 950 meters of this underground project have been worked by 19 miners drilling, removing, loading, and hauling the material out. The underground operation removes 20 tons of contact zone material a day. For comparison, a single truck in the open-pit operation removes that much material five times every hour.

	While the underground ore is currently being removed by a pulley system, it will be
	necessary to develop a system that allows for a far greater production capacity when
	the project goes into full commercial production. Photo by Andrew Lucas/GIA.
The key to expanding the underground mine from a pilot project into production is to duplicate the production capacity of the open-pit mine, which is around 8,000 tons of ore a month. This would only be made possible by increasing the scale of the operation, installing a proper production hauling system, and engineering to support these larger systems. Columns are needed to support underground operations in mined areas as well as areas that are not being mined. Currently the main tunnel is 2x2 meters. To expand for production, the tunnels would need to be at least 6x3 meters. The future vision is to have a decline ramp where trucks could drive in and be loaded with ore as it’s removed from horizontal tunnels.

Robert Gessner said that one of the big differences between the open pit and the underground operation is that in the open pit, even though all the ore goes to the washing plant, 65 percent of production is achieved in the pit and 35 percent through recovery at the washing plant.

For this pilot project as well as any future underground operations, all the ore will still go to the washing plant, but due to the fact that there is more contamination, the majority of production—about 80 percent—will be achieved at the washing plant before the ore goes to the sorting house. With this in mind, Gemfields has focused on expanding the capacity of its washing plant.

While this pilot project is ongoing, new open pits are expected to come into production in the future as a result of ongoing prospecting and exploration. This means open pit production is expected to continue to be the main source of Kagem emeralds for many years.

	The current tunnels would have to be significantly expanded in order for the underground
	operation to reach production levels anywhere near those of the open-pit operation.
	Photo by Andrew Lucas/GIA.
The underground operation is still in its experimental stages. However, the geology is more clearly visible in the underground tunnel. As additional tunnels are opened, they will add important information that can be used for other exploration projects.

	Prospecting and Exploration
Extensive prospecting and exploration are the keys to ensuring and securing the production and life of a large-scale mechanized mine like Kagem. Gemfields has invested a lot of capital in both core drilling and bulk sampling since it took over the mine.

Since emerald prospecting in the Kafubu area has never paused in the past 100 years, earlier investigations formed a solid base for current and future work. Prospecting’s main goal is to better define the underground distribution of the ore-bearing schist and the quartz-tourmaline veins. Meanwhile, the exploration also allows the geologists to form a better estimate of how much waste and ore they need to handle to recover the emeralds. In earlier stages, both magnetic and radiometric surveys were used to locate the talc-magnetite schist and the quartz-tourmaline veins. Since the schist contains magnetite, it has a higher magnetic reactivity than other rocks in the area. The presence of certain elements in pegmatites and quartz-tourmaline veins allows them to be picked up by radiometric surveys.

After the location is targeted, finer resolution methods like core drilling, petrographic analysis, and geochemical analysis are applied to more accurately delineate the talc-magnetite bodies and the quartz-tourmaline veins. For the past three years, intensive core drilling and bulk sampling have been done by the mine’s exploration team within selected areas.

In addition to the big pit, Kagem has developed several bulk-sampling pits. Some of them will be in production in the near future. Reproduced courtesy Gemfields.
In the core library at the Kagem mine, thousands of boxes are stacked in the two storage rooms. Senior Geologist Robert Gessner explained that, for the past three years, Gemfields had done a huge amount of core drilling in some potentially productive areas within its property. The total drilling length is about 36 kilometers. Exploration teams work two shifts per day, six days per week. They must complete 30 meters of hard-rock drilling each day.

After the core is removed, petrographic work and geochemical analysis are applied to the talc-magnetite schist body. The concentrations of trace elements chromium and vanadium were measured using X-ray fluorescence spectroscopy. The drilling cores are studied meter by meter and all the data is input into a geological three-dimensional modeling program called SURPAC to help construct a 3-D model of the underground geology. The modeling is focused on the distribution of the talc-magnetite schist and the reaction zones where emerald mineralization takes place.

After completing thousands of core drillings, geologists use the data to construct a 3-D model of the host rocks and the pegmatites below the earth’s surface. Reproduced courtesy Gemfields.
Every drill core is important as a reference for future mine planning, so they are all very well catalogued and preserved as individual sample assets. Mine personnel can easily access them for further study. The cost of core drilling is $500 per meter. The total amount that Gemfields has invested in this process is tremendous, but it’s a necessary expense for starting any serious mining project and allowing the miners to understand as much as possible about the geology of the area. It also helps them determine the most cost-effective mining technique. As Robert Gessner repeatedly said, “Mining is dictated by the geology.”

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	Core Library
After core drilling and geology modeling are done, the real digging begins. This is the pre-production stage called bulk sampling. As the geologists say, you can never be sure about the geology until you open and sample the pit. Excavators are used to open a bulk sampling pit. The property contains six potentially productive areas that need to be explored in addition to the big open pit now in production. Our team visited two of those potential pits, Fibolele and Libwente.

Fibolele is one of Kagem’s bulk sampling pits. All bulk sampling pits are tightly secured by a 24/7 patrol of security staff and dogs. Photo by Stanislas Detroyat.
When Vincent Pardieu visited the mine in 2011 and 2012, exploration and sampling of Fibolele had just started. The wall of this “baby pit” has been continually pushed back over the past two years. The goal of the bulk sampling projects is to determine the potential for a second open-pit operation. Security is tight at the testing pits. Guards and dogs patrol them 24/7, since the loss of any pockets of stones can change the project’s determination from profitable to unprofitable. At the time of the authors’ visit, this pit was showing a good return rate.

Later, during our visit to the sorting house, we saw some interesting samples of promising quality coming from Fibolele. We were able to select some of these samples as reference specimens for the GIA Laboratory. We were told that, due to the promising results from phase-one sampling, this pit is now engaged in phase two of bulk sampling.

The authors visited another bulk sampling pit at the concession, called Libwente South. Gemfields has done about 17 kilometers of core drilling in this area, and results indicate great potential. In the three months before the authors’ visit, mine operators were working on removing the topsoil, and the teams are now trying to find a balance between mining costs and return. This pit will be in production in the very near future. Standing on the edge of the pit, the authors were able to clearly see the part of the quartz-tourmaline veins and the talc-magnetite schist bodies that have been exposed.

The Libwente South exploration pit is currently still in its early stages, but exploration results have shown that it has great potential. Photo by Stanislas Detroyat.

	Production
The phlogopite-biotite contact zones are associated with two pegmatites, a quartz-tourmaline pegmatite and a feldspar-tourmaline pegmatite. The better-quality emeralds are associated with the contact zones at the reaction areas with the quartz-tourmaline pegmatite. Gemfields auctions are broken into two quality ranges: one auction for lower-grade material and one auction for higher-grade material.  The charts below show Kagem production amounts in terms of rock handling and total gemstone production since January 2005.

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	Rock-handling Totals

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	Production Levels

	Expedition guest Stanislas Detroyat displays an emerald crystal from among the sorted
	parcels of emeralds recovered from the pit. Photo by Vincent Pardieu/GIA.

	Washing
Operations at the processing plant involve ore crushing and washing, with no introduction of chemicals. A triple-decker screen breaks the material down by size and final pickers pick out the emerald crystals by hand under the watchful eye of security.

The large quantity of production is evident at the Kagem mine when you see truck after truck removing ore from the pit for transport to the washing plant. Photo by Vincent Pardieu/GIA.
Once the ore is transported to the washing plant, it follows a process that is typical of sophisticated colored gemstone mining operations. Screens are used to break down the material by size and then washers remove the silt to expose the potential emerald-bearing schist for hand pickers to examine.

During our visit we observed various interesting improvements that Gemfields has implemented in their washing plant, which was renovated in December 2013. The picking area was enclosed and the lighting and security environment improved. Its capacity is currently 40 tons per hour, but now it can operate 24/7 with three eight-hour working shifts, while during author Vincent Pardieu’s last visit it was only working two eight-hour shifts. Low-quality material is processed at night, while higher-quality ore is sent to the washing plant during the day. The plan is to continue improving the process in order to reach 150 tons per hour. When they reach that capacity, the Kagem washing plant will be able to absorb the quantities expected to be produced from new pits like Fibolele and also the underground operation when it reaches production level.

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	The Washing Plant

	Sorting and Grading
Opening the safe box is the first task for Kagem’s sorting house staff. Different-sized boxes are used for ores or stones of different sizes. Emerald-bearing ores can be transferred directly from the open pit, from the underground mining operation, or from the washing plant, and each safe box has four locks to secure the stones inside and to allow for the assignment of security responsibilities to different departments. It can be weeks or even months between the time a box is opened and the time a stone is referenced. Very strict rules are applied at each step, throughout the entire process. Weight is checked at each step, and waste is retained to make sure the total weight is consistent.

Gemfields takes security very seriously. Each safe box has four locks to protect the interests of all parties. Photo by Vincent Pardieu/GIA.
According to sorting house staff, they process about 200 kg of ore per day, for a total of 20 to 30 tons a year. Lower-quality materials are cobbed first to remove overburden, while the higher-quality materials are individually cleaned by high-pressure air.

	Cobbing is an art and a very important step that removes highly included areas from
	the emerald rough. Photo by Andrew Lucas/GIA.
In the sorting house, staff members do their best to recover every piece of emerald. The authors were introduced to a newly designed and installed in-house washing system by Mr. Etienne Marvillet, the mine’s production manager and one of the system’s designers. This machine’s operation is similar to the machines in the washing plant but on a much smaller scale designed to handle finer materials. It is a very handy tool for the sorting-house staff because it allows them to process the material onsite without going back to the washing plant. This also decreases the security risk and the total potential loss.

	A first step in the process is to remove the emeralds from the schist. Photo by Vincent
	Pardieu/GIA.
Gemfields’ ability to deliver quality parcels for auction is directly related to the quality of their reference sets. Gemfields has three reference sets, one at the sorting house at the Kagem mine in Zambia, one in India, and one in the UK. The reference sets were built from production at various locations in the mine over a number of years. This is a highly important aspect of the grading system, as incorporating older stock into the system helps to ensure consistent grading as new production comes forward.

The grading system is internal to Kagem production and has been a key to the success of their auctions. Buyers have come to trust the grading of the parcels and rely on them to be consistent over the years. Gemfields does not believe in offering mixed-quality mine runs in huge parcels. They believe their customers and shareholders are better served by offering properly graded parcels covering all their production grades.

	This grader must determine the quality of this large emerald crystal so it can be
	accurately represented at auction. Photo by Vincent Pardieu/GIA.
The grading set has six size classifications that represent the range of sizes coming out of Kagem production. Size classification is important since small stones are often less included than larger ones. The production is then further classified by separating material with a strong blue secondary modifying hue from the purer green material. After the production is graded to this point, more stringent grading procedures refine it into further classifications. Gemfields then evaluates the color, clarity, and transparency. For transparency, graders separate cleaner facet-grade material from hazy material used for cabochons and beads. Once the stones are placed into purer green or modified-by-blue categories, they are graded into about 14 additional classifications.

	The reference set allows for the consistent grading that has a lot to do with the success
	of Gemfields auctions. Photo by Vincent Pardieu/GIA.

	Collecting Reference Samples
In the Summer 2014 issue of Gems & Gemology, GIA researchers—including the Bangkok lab’s Vincent Pardieu—published a preliminary study on the three-phase inclusions in emeralds from different sources. They studied a selection of samples from the GIA global reference collection, including stones from the Kafubu area. The study was part of GIA‘s ongoing research on the determination of colored stone origin, with a focus on emerald, ruby, and sapphire. This research has taken place under the direction of the GIA Bangkok lab since 2008.

The ultimate goal for a field gemologist is to dig reference gemstone samples right out of the ground themselves while completely documenting the location and circumstances. Photo by Vincent Pardieu/GIA.
The first day of our visit to the Kagem mine, we were taken down to the bottom of the large open pit. Miners were using an excavator to remove the ore from a local shear zone and we were allowed to pick emerald samples from the removed material. Vincent Pardieu collected several samples that were still in their matrix. All had outstanding color and transparency. Tao Hsu found a large emerald crystal with nice color and shape. Later, Vincent and Tao followed the big stone to the sorting house and witnessed it being cleaned. The rest of the samples will be kept in their matrix and shipped by Gemfields to the GIA Bangkok lab for further study.

	As Tao looks on, a member of the sorting house staff uses a high-pressure air tool to
	clean quality samples. The sample he’s working on is the one Tao collected earlier in
	the day and it’s destined for the GIA reference database. Photo by Vincent Pardieu/GIA.
During this visit, members of the group also collected samples from other mining operations in the Kafubu area. When researchers collect samples onsite and can verify that they came directly from the pit, the samples are considered type A samples—the most valuable category for research purposes. This and future collection expeditions will help to enrich the GIA reference collection. More complete studies based on these samples will be presented in future Gems & Gemology and GIA web articles.

	Preliminary Gemology
As with all emeralds, Kagem emeralds owe their rich green color to the presence of chromium and vanadium. That color is often modified by iron, which is commonly present in emeralds mined from pegmatites intruding into schists. The presence of iron is detected by chemical analysis using EDXRF or LA-ICP-MS, but also by studying UV-Vis spectra.

Kagem emeralds form in a reaction zone within a quartz-tourmaline or quartz-feldspar pegmatite. With the presence of some talc, magnetite, and mica-rich schist, mineral inclusions of magnetite, mica, quartz, feldspar, or tourmaline are common. As fluids play an important role in the formation of these emeralds, they most commonly contain multiphase inclusions. The inclusions usually consist of a liquid and a gas bubble, and often a solid doubly refractive crystal.

There’s more information about the gemological characteristics of emeralds from the Kagem mine, and about methods the GIA Laboratory can use to separate them from emeralds from other deposits, in an article about emeralds with multiphase inclusions published in the Summer 2014 issue of Gems & Gemology.

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	Inclusions in Emerald

	Mine Security
After the size of the pit, the next thing that struck us at Kagem was the level of security. According to a member of the security staff, there are 150 security guards and 50 security dogs working around the entire mining concession. When miners are in the pit, there are always two security guards monitoring the operation. The chiselmen were closely monitored as they removed the emeralds from the pit and placed them in the lock boxes.

Management and security personnel watch over the workers as they chisel the rock and place emeralds into the red lock boxes. Photo by Vincent Pardieu/GIA.
Everyone who leaves the pit undergoes a vehicle, bag, and body search. This includes visitors, Kagem staff, and Kagem management regardless of level. Security checks also occur at the washing plant and the sorting facility, as well as when you leave the mine grounds. The security procedures are applied evenly to everyone that goes through the check points. Closed circuit television monitoring also takes place in the sorting house.

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	Mine Security
Even with all that security, we still saw some people, described by the mine staff as illegal miners, trying to retrieve emerald-containing pieces of ore from the license areas and mine dumps. In the days following our visit, Vincent Pardieu, Stanislas Detroyat, and Didier Gruel spent several days visiting other emerald mining operations in the Kafubu area. During those visits, they met several of those individual miners, either in the early mornings as they returned from a long night of prospecting, or in the evenings when they were just setting out. Indeed, it seems that hundreds of people cross into the Kagem mine to look for emeralds. According to them, their main market is local or foreign merchants (mainly from West Africa), who wait for them each day in nearby villages or in Kitwe. Interestingly, among the most powerful tools used by these illegal miners and traders are mobile phones, which is why mobile phones are not allowed inside the Kagem operation.

	Gemfields and Kagem
Gemfields places great importance on the people involved in its Kagem mining operation. They devote a lot of time and effort to finding, recruiting, and keeping talented and highly motivated people with passion for their work. Gemfields also believes in developing people and helping them advance into higher positions and further the company as they further themselves. The working environment is very much focused on a team effort.

The Kagem operation provides employment and skill development for locals in a number of positions at the mine. Photo by Vincent Pardieu/GIA.
Another Gemfields advantage is the working capital they invest in properly running the mining operation. This allowed initial investment in equipment and the ability to spend a year cleaning the pit so the proper mining methodology could be implemented. By bringing in the proper equipment, building suitable structures, applying the correct techniques, and training the staff, Gemfields has been able to turn local employees, who were highly unmotivated under previous management, to being highly motivated.

People from the Kagem mine state that since Gemfields took over and started producing, the mine has been profitable for the first time in its life. After its first 19 years, Gemfields came in and turned it into a profitable mining operation in just six years.

The Kagem mining operation is a colored stone mining project combining heavy investment with a high degree of sophistication. Photo by Andrew Lucas/GIA.
Gemfields is a publicly traded company on the London Stock Exchange. It is a subsidiary of Pallinghurst, another publicly traded company with very strong experience in platinum mining. Gemfields owns 75 percent of the Kagem operation. The other 25 percent is owned by the Zambian government. The Kagem mine is the only operating emerald mine in Zambia that shares a percentage ownership with the government. Gemfields took over their 75 percent share from the previous management.

Since it’s a publicly traded company, Gemfields’ corporate strategy boasts a high level of transparency—a quality that is not universal in the colored gemstone industry. This transparency has helped build the company’s relationships with its government partner at Kagem as well as with employees, shareholders, and the rest of the colored gemstone industry. The Zambian government has representatives on the Kagem board, including the chairmanship.

	Community Relations and Employees
Gemfields has an active program devoted to evaluating local agricultural, educational, health, and cultural factors such as chiefdoms. The company works with local communities to identify ways of improving these components in a program devoted to social beneficiation.

The company has assigned a full-time community project coordinator to work onsite to implement the program. Securing the food supply is probably the most important factor in many local communities. The Kagem operation fully supports two local farms, helping those local farmers support their own families, sell their products, and provide fresh vegetables to the mine.

	Local farmers benefit from support by Gemfields’ Kagem mine. They can sell the
	vegetables they produce in local markets and also for serving in the mine kitchen.
	Photo by Robert Gessner.
To support basic education of the local population, Gemfields has provided a school and teachers’ quarters, while the Zambian government provides the teachers. A budget of $1.2 million has been approved for a two-year project to build a secondary school and health center in an area where none existed. The health center serves 5,000 local people. Children’s and maternity wards are also being developed.

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	Community Projects
A large part of Gemfields’ relationship with the local community comes from employing locals and training them in skills that prepare them for the future. New hires get a five-year contract rather than the two-year contract that is more normal for mining staff. Employees are bused in every week and taken home at the end of the week. Accommodations and meals are provided onsite and employees and their immediate families get medical coverage. Kagem is also proud of its safety record of over 3 million man-shifts without an injury.

	Kagem’s excellent safety record is recognized by the Mines Safety Department of Zambia.
	Courtesy Gemfields.
Gemfields’ Kagem operation currently has about 570 employees. About 50 expats hold most of the management positions. However, Gemfields is dedicated to training local employees to improve their skill levels in hopes that they will eventually take management positions and run the operation. Opportunities in Zambia for locals to become mining engineers and geologists are limited, but Gemfields’ goal is to train local employees in those professions.

	Kagem trains its local employees to help them gain mining skills that will benefit the
	future of Zambian mineral resources. Photo by Vincent Pardieu/GIA.

	Auctions
Gemfields’ operational transparency is reflected in its auction system. Auction sales results are public knowledge, providing assurance to the Zambian government that they are being informed about actual production revenue and that the production was sold at market value. The auctions also provide complete revenue transparency to shareholders. Many in the colored gemstone industry find the Gemfields auction system to be a very transparent and fair way to offer rough gemstones for sale. All trade members invited to the auctions have an equal chance of acquiring the rough parcels they need.

Download Emerald Production Auction Results (PDF)

	Gemfields provides auction results for both its high- and lower-quality emerald production. This level of transparency is unusual for the colored gemstone industry. Reproduced courtesy Gemfields.
A key factor in the auctions’ success is the consistent sorting and grading of the rough emerald parcels that takes place at the mine. Over the years, Gemfields has had feedback from auction buyers regarding their needs, and those buyers have come to trust the consistency of Gemfields grading. In addition, customers who bought a certain grade several years ago can be confident that they can bid on a parcel with the same grade at a future auction and be able to match the stones from both. The auctions also create a sense of trust in that everything is on the table and there are no behind-the-scenes deals.

Revenue per carat has been consistently rising over the last six years at both the high- and low-quality material auctions. This increase in the per-carat price has helped to ensure that the revenue per mined ton is higher than the per-ton cost. This is a critical calculation for the continued profitability and sustainability of the mine.

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	Per-carat Prices

	Summary
Gemfields has achieved impressive results at the Kagem mine so far. They have taken the mine from a long history of loss and turned it into a profitable venture for all parties. The annual revenue has increased and the mine is now profitable and paying increasing royalties to the Zambia government. They have demonstrated that proper mining methodology, community relations, environmental protection, transparency, and government partnerships actually improve the gemstone mining business. But the impact of this mining operation probably goes far beyond just the results obtained at this mine.

Gemfields has shown that proper funding, wisely invested in the right mining property, can result in profits. As a publicly traded company, they have also made an important contribution to the movement to attract investors into the colored gemstone industry. Their auction system has been a success in terms of customer acceptance and satisfaction, transparency for all parties, increases in per-carat value, and company profitability. The Kagem mine is a remarkable example of the right combination of geology, mining methodology, innovative business strategies, best business practices, and marketing.

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	Kagem’s Revenue, Royalties, and Profit @chapter:22


Publication Year: 1985 Title: Interesting Red Tourmaline from Zambia Abstract: This note describes the study of five small, gem-quality crystals and crystal fragments of a brownish red to red tourmaline from a new locality near Chipata, Zambia. The mineralogical nature of these tourmalines is briefly discussed. X-ray diffraction indicates that these tourmalines belong to the schorl-dravite series. Refractive indices, birefringence, specific gravity, and other gemological properties are given, as well as comments on the inclusions. This material is very similar in appearance, gemological characteristics, and chemistry to the red tourmalines from Kenya. @chapter:5


Publication Year: 1996 Title: Opal from the Shewa Province, Ethiopia Abstract: Opal occurs as nodules in volcanic rocks at a new gem opal locality in the Menz Gishe district of Shewa Province, Ethiopia. The opal field, still in the early stages of exploration, extends over several square kilometers. Opals from Shewa Province have near-colorless to white, yellow, orange, gray, or brown body colors; some show face-up play-of-color, and many have contra luz play-of-color. The gemological properties are consistent with those of other natural opals, and small particles are common inclusions. Preliminary stability tests indicate that much of the material absorbs water and some crazes when exposed to light and heat. @chapter:39


Publication Year: 2016 Title: Polymer-Treated Hessonite Abstract: Figure 1. These three rough hessonite samples (17.92 grams total) are joined by a polymer, which is also found in surface cavities and joints. The treatment is evident from the rough’s “oily” look. Also note the visibility of fractures in the 5.31 ct (left) and 5.35 ct (right) cut samples. Photo by Gagan Choudhary.

	Early in 2016, gem merchant Abdul Hafiz (Jaipur, India) showed this contributor a parcel of orangy brown rough hessonite he had purchased, said to be “glass-filled” hessonite. Upon initial observation, the specimens appeared to be treated, as individual crystals were stuck together (figure 1). This is commonly seen in glass-filled corundum rough; however, the typical glassy surface was absent. Rather, the surface appeared greasy, as if it was heavily oiled. Since the crystals were stuck together, it was obvious that some more stable form of treatment has been performed. Further testing was conducted to identify the treatment.

	Under 10× magnification, the joints and cavities showed a concentration of a foreign substance that was readily indented with a metal pin, ruling out the presence of glass. Because of the unpolished surface, we could not see the  filler, but the stone was transparent enough for infrared spectroscopy. The spectra showed strong features at approximately 3060, 3032, 2923, and 2871 cm–1; these peaks are associated with polymer. Other absorption features were consistent with grossular garnet, specifically hessonite and tsavorite, according to the laboratory’s database.

	To check for a polymer filler and record gemological properties, two specimens were faceted, weighing 5.35 and 5.31 ct, respectively (again, see figure 1). Both specimens gave an RI of 1.745 and a hydrostatic SG of 3.60, within the range for hessonite (M. O’Donoghue, Gems: Their Sources, Descriptions and Identification, 6th ed. Butterworth-Heinemann, London, 2006). Both displayed a strong roiled or “heat wave” effect and numerous transparent rounded to elongated colorless crystals, features consistent with hessonite. The stones had obvious fractures visible to the unaided eye. When magnified, these fractures displayed thick and cloudy patches (figure 2), suggesting that a foreign substance was used to create an uneven filling. None of the iridescence or color flashes typically associated with a filled fracture were visible. Both faceted stones also displayed characteristic polymer-related peaks in IR spectroscopy.

Figure 2. Fractures of the cut samples display thick and cloudy patches, suggesting uneven filling. Photomicrograph by Gagan Choudhary; image width 6.35 mm.

	This was our first encounter with a polymer-treated hessonite. Because the fractures were eye-visible, it is unclear how much value the treatment adds to these low-grade stones. According to Mr. Hafiz, the treatment is performed to stabilize the rough for cutting and polishing; otherwise the highly fractured material crumbles while processing. He added that hundreds of kilograms of such rough (reportedly African) have been sent to China for treatment. @chapter:6


Publication Year: - Title: Bert Krashes (1923–2014) Abstract: At GIA’s cramped laboratory in New York City, Robert Crowningshield had just spotted the spectroscopic line for differentiating between natural-color and irradiated diamonds. It was January 1956. Elated, he shouted for colleague Bert Krashes to come look over his shoulder. But Krashes was out to lunch, literally. It was probably the last time Krashes ever missed such a breakthrough during his decades-long tenure with GIA.

The post–World War II market for jewelry was just beginning to pick up, and consumer interest in diamonds had surged. Trained as a draftsman, Krashes was a store manager at Finlay’s Fine Jewelry in New York City when he enrolled at GIA on the GI Bill in 1948.

Studying under Crowningshield and Richard Liddicoat, the Bronx native earned his GG diploma in 1949. Thanks to his inquiring mind and gentle, engaging manner, Krashes was tapped to join GIA as an instructor later that same year. When Eunice Miles came aboard in 1953, the entire New York staff numbered three.

A fixture on 47th Street, Krashes nevertheless willingly hit the road in the 1950s to promote GIA’s new diamond grading system. Traveling with Crowningshield, he brought the grading gospel to mom-and-pop jewelry stores from coast to coast, setting up traveling classrooms across the United States.

“We created a whole new world for jewelers who up to that time had relied only on a loupe,” Krashes said. “Can you imagine their delight when we showed them what they could do with a microscope and other diamond-grading equipment?”

Krashes’s days on the road were over by 1970, about the time his frontline service to GIA began to garner formal recognition. That same year, he was voted honorary vice president of the Gemmological Association of Canada; in 1983, he and Crowningshield were co-recipients of the American Gem Society’s Robert M. Shipley Award.

Krashes served as vice president and director of the New York lab from 1977 through 1988. At his retirement party, GIA president Bill Boyajian praised the administrator as a “stalwart in New York” and “an outstanding educator, gemologist, and association executive.” Krashes remained on the GIA Board of Governors until 1998, then acted as an advisor until passing away in January 2014.

In recognizing Bert Krashes with its Shipley Award, the American Gem Society praised his artistry and discipline. To those attributes, his friends at GIA added a third—chivalry. He was a gentleman of the old school, and he applauded that quality in others. When William Goldberg, part owner of the superb Premier Rose diamond, picked up a GIA diamond report for the gem, Krashes asked if his secretary could see the diamond. He was impressed when Goldberg unhesitatingly placed the 137.02 ct D-color stone in the palm of her hand.

“That’s the type of jeweler I remember from my early days. They were gentlemen who had a sincere appreciation of gems in addition to sophistication and integrity,” Krashes said in a 1988 interview. He might just as well have been describing himself. @chapter:24


Publication Year: 1984 Title: Gem-Quality Red Beryl from the Wah Wah Mountains, Utah Abstract: A detailed investigation of the gem-quality red beryl from the southern Wah Wah Mountains, Utah, has confirmed the unique mineralogical and gemological character of this material. At the Violet Claims, red beryl is found associated with minor bixbyite in a volcanic rhyolite host rock. Analytical data gathered on the red beryl indicate relatively high contents of the minor or trace elements Mn, Ti, Zn, Sn, Li, Nb, Sc, Zr, Ga, Cs, Rb, B, and Pb, which are generally low or absent in other gem beryls. Measured refractive indices (1.564-1.574), specific gravity (2.66 -2.70), and unit-cell parameters (a= 9.222 Aº, c= 9.186 Aº) of the red beryl are distinct from most other beryls. The red beryl is thought to have crystallized along fractures, in cavities, or within the host rhyolite from a high-temperature gas or vapor phase released during the latter stages of cooling and crystallization of the rhyolite magma. @chapter:6


Publication Year: 2004 Title: Winter 2004 Gem News International Abstract: Diamonds
            A Natural Diamond with Very High Ni Content
Colored Stones and Organic Materials
            Adularescent Chalcedony from Iran
            Clinohumite from the Pamir Mountains, Tajikistan
            Corundum-Fuchsite-Kyanite Rock from India
            A New Gem Material from Madagascar: A Mixture of Cristobalite and Opal
            Jeremejevite from Madagascar
            Kyanite from Tanzania
            Sapphires from Afghanistan and Pakistan
            Sapphires from Baffin Island, Canada
            Unusual Star and “Cat’s-Eye” Sapphire
            Large Cat’s-Eye Topaz from Ukraine
            A Notable Triplite from Pakistan
            Update on Several Gem Localities in Zambia and Malawi
Inclusions in Gems
            Barite “Spears” in Fluorite
            Arizona Peridot with Unusual Inclusions
            Double-Eye Chatoyant Quartz
            Graphite Inclusions in Quartz from Brazil
            Quartz with Molybdenite
            Rutile “Moth” in Quartz
Synthetics and Simulants
            Synthetic Verneuil Corundum with Unusual Color Zoning
            Imitation Clam “Pearl”
Announcements
            Visit Gems & Gemology in Tucson
            Gem Treatment Seminar in Tucson
            2005 Gem-A Field Trips
Exhibits
            Cartier Collection in Houston
            Native American Jewelry at AMNH
Conferences
            WJA in New York
            PDAC 2005
            BaselWorld 2005
            Russian Gemology
            GemmoBasel 2005
            Diamonds at GAC-MAC
            Bead Expo in Miami
            Goldschmidt Conference

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Publication Year: 2020 Title: Unusual Violet Maxixe Beryl Abstract: Figure 1. This 26.72 ct Maxixe beryl has an unusual violet color. Photo by Diego Sanchez.

Recently examined in the Carlsbad laboratory was a 26.72 ct transparent violet modified cushion mixed-cut stone (figure 1). Standard gemological testing revealed a refractive index of 1.583–1.592 and a specific gravity of 2.78, both consistent with beryl. Using plane-polarized light, pale purple and saturated blue pleochroic colors were observed. A uniaxial optic figure was seen at the girdle, and the optical orientation of the stone showed the stronger blue pleochroic color down the optic axis direction. The stone was inert to long-wave UV light and fluoresced weak greenish yellow to short-wave UV. Viewed with fiber-optic light during microscopic examination, it displayed a few scattered blocky crystals, platelets, and needles, confirming natural growth origin. No coatings were seen on the surface under reflective light. Other than the unusual violet color, these properties were consistent with Maxixe beryl.

Figure 2. The violet beryl showed a typical UV-Vis-NIR spectrum for Maxixe beryl. Pleochroic colors were calculated from the spectra and revealed a blue (o-ray, dark blue trace and color swatch) and light violet (e-ray, pale purple trace and color swatch) pleochroism.
Advanced testing by LA-ICP-MS revealed that the stone lacked iron. This result was consistent with Maxixe beryl, in which iron is too low to be measured (I. Adamo et al., “Aquamarine, Maxixe-type beryl, and hydrothermal synthetic blue beryl: Analysis and identification,” Fall 2008 G&G, pp. 214–226). Maxixe beryl normally has a blue to violet blue bodycolor, but this stone showed an unusual violet color. The UV-Vis-NIR spectrum (figure 2) showed absorption bands between 500 and 700 nm and a broad band near ~690 nm. This spectrum was consistent with Maxixe beryl (again, see Adamo et al., 2008). While Maxixe beryl has been found to be colored by natural irradiation, it can also be produced by artificial irradiation. Some of these “Maxixe-type” beryls produced by artificial irradiation are known to fade when exposed to “mild heat or strong light” (see Winter 1997 Lab Notes, p. 293). However, there is no conclusive test to determine whether Maxixe color results from natural or artificial irradiation, and as such, beryl in the blue to violet color range that shows the type of visible spectrum previously mentioned is designated simply as the Maxixe variety of beryl by the GIA laboratory.

Figure 3. From the violet beryl material provided for this study, a wafer was fabricated in order to directly measure the absorption spectra while conducting a fade test by placing the sample four inches away from an intense 150-watt halogen light source. The results, normalized to a 25 mm path length, confirmed that the color became less saturated over time with exposure to light. Most of the color loss came from the o-ray direction (left).

Figure 4. The polarized visible spectra were used to produce color swatches of the ordinary-ray (E ⊥ c) and extraordinary-ray (E || c) color normalized to a 25 mm path length to illustrate the change in color during fade testing over a period of 32 hours at four-hour intervals.
A small sample cut from the same rough as the 26.72 ct violet beryl was provided by lapidary Nolan Sponsler for destructive testing in order to evaluate the color stability of this material. An optically oriented wafer, 4.45 mm thick and normalized to a 25 mm path length in order to better observe the change in color, was fabricated from this sample with parallel polished windows that are parallel to the optic axis to allow measurement of the o- and e-rays. UV-Vis-NIR spectra were collected on the sample prior to fade testing and at four-hour intervals of exposure to a 150-watt halogen bulb at a distance of approximately four inches from the bulb to avoid any significant heating (figure 3). The results showed fading of the sample until its color was very pale (figure 4), confirming that this material may fade. One should avoid prolonged exposure to light and store it in a dark environment to preserve the color.
This violet Maxixe beryl was purported to be from Santa Maria de Itabira, Minas Gerais, Brazil. It is notable for its unusual color and its fantasy cut design. In addition to this violet Maxixe beryl, another violet beryl group mineral named “johnkoivulaite” was documented in 2019 (see Fall 2019 GNI, pp. 454–455); that new beryl is from the Mogok mining area in Myanmar. However, standard gemological properties clearly separate the two violet beryl minerals. Even though this beryl owes its appealing violet hue to what would be considered an unstable color center, the color should remain intact if prolonged exposure to intense light sources is minimized. @chapter:19


Publication Year: 1987 Title: Summer 1987 G&G Lab Notes Abstract: Needle-Like Inclusions in Epidote
A New Opal Assemblage
A Cultured Pearl Puzzle
A "Fossilized Pearl" from Utah
Cat's-Eye Peridot
Dyed Yellow Quartzite
Synthetic Blue Sapphire
Synthetic Yellow Sapphire
Unusual Inclusions in Heat-Treated Blue Sapphire
Dyed Yellow and Reddish Orange Serpentine
Sapphirine, a Rare Gemstone
Bicolor Topaz

To view the full section, download the PDF above. @chapter:2


Publication Year: 2023 Title: French Jewelry Brand Fred Creates High Jewelry Collection from Synthetic Diamonds Abstract: While industry-leading diamond brand De Beers announced the cessation of sales for lab-grown diamond products, jewellery brand Fred under the LVMH group opted to use special blue synthetic diamonds in creating high-end jewellery, marking itself as the first brand to do so. This decision followed advancements in synthetic diamond technology since 2010.
On September 19, Fred unveiled an 8.8-carat blue synthetic diamond, indistinguishable to the naked eye from natural diamonds. This significant diamond will be featured prominently in a newly designed jewellery collection comprising necklaces, rings, and earrings, accentuated with genuine diamonds.
Charles Leung, CEO of Fred, explained that the use of synthetic diamonds stemmed from a specific need within their redesigned jewellery line for diamonds with unique color and size characteristics. Synthetic diamonds were considered the most suitable option, not to capitalize on the trend of lab-grown diamonds in high-end jewellery, but due to successful collaborations with various synthetic diamond manufacturers, culminating in the production of a precisely sized diamond that met their requirements and received certification from the Gemological Institute of America (GIA).
Prior to this, De Beers, a major player in the diamond industry and the world's largest diamond producer, had entered the lab-grown diamond market in 2018 with a $90 million investment over a four-year period. However, on September 13, De Beers announced the complete cessation of all lab-grown diamond sales. This decision was primarily driven by economic challenges in the United States, a test market for lab-grown diamond jewellery, which had a continuous impact on diamond jewellery prices, including lab-grown diamonds.
According to Bain & Company market data for 2020, natural diamond production totaled 111 million carats, while global lab-grown diamond production was only 7 million carats, representing just 10% of global diamond production (up from 3% in 2017).
Meanwhile, mid-range jewellery brands like Pandora decided to incorporate lab-grown diamonds in their jewellery production to promote social and environmental sustainability policies effectively. Olivier Kessler-Gay, Pandora's Managing Director for Western Europe, announced the complete cessation of natural diamond use in their jewellery since two years ago. Previously, Pandora used natural diamonds in just 50,000 pieces out of 105 million pieces produced annually. In August, Pandora introduced three new jewellery collections featuring lab-grown diamonds, exclusively available in the United States and the United Kingdom. Beyond cost savings, using lab-grown diamonds reduces production costs by up to one-third compared to natural diamonds, furthering their sustainability initiatives through the entire production process, including cutting with alternative energy sources.
Every jewellery manufacturer using lab-grown diamonds does not disclose the source of their products, emphasizing their ability to meet both environmental and social needs for sustainable production, from creation to cutting using alternative energy sources. @chapter:38


Publication Year: - Title: Mogok Expedition Series, Part 1: The Valley of Rubies Abstract: Mogok, Myanmar, is also known as the "Valley of Rubies." Photo by Andy Lucas, ©GIA.

                      There’s an old saying that whatever you are doing at the start of the year will reflect on the rest of the year. Hopefully this is true, because for the authors, 2014 truly started out right. The authors spent that time exploring the famed and captivating gemstone areas collectively known as Mogok, or the Mogok Stone Tract. Mogok, located in Myanmar (Burma) is also referred to as the "Valley of Rubies," a name made famous by the novel Mogok, the Valley of Rubies by Joseph Kessel and Stella Rodway.

Vincent Pardieu, senior manager of field gemology at GIA's Bangkok lab, has traveled extensively to Mogok in the past. For foreigners, travel to Mogok had been next to impossible over the last decade, but the Myanmar government recently loosened restrictions, and Vincent visited there in the latter part of 2013. At year’s end, Vincent invited Andrew Lucas, manager of field gemology for GIA education, to travel to Mogok with him. Andrew had been to Myanmar three times before but never to Mogok, as it had always been off limits. The 2013 and 2014 trips were the first visits to Mogok by GIA gemologists in over a decade, and the first time GIA education had someone on the ground in the area.

The authors left Bangkok on December 28, arriving in Mogok the same day. Vincent’s mission was to collect gemstone samples for the lab’s origin-of-gemstones research and to document the industry. Andrew was there to document the industry for GIA education. The expedition to a legendary gemstone source that many believe is unequalled had begun.

	Top-quality Burmese rubies are the standard by which the world's production is judged. A record selling price for ruby was set at Christie's in St. Moritz on February 15, 2009, when an 8.62 carat cushion-shaped ruby realized a price of $425,000 per carat. This record-breaking gemstone was termed the desired "pigeon's blood" red used for highly sought rubies from Myanmar. Photo courtesy of Christie's.

	Myanmar
Myanmar is an amazing country with an incredibly diverse population. The country borders China, India, Thailand, Laos, and Bangladesh. It also reaches the shores of the Andaman Sea and Bay of Bengal. The country is home to approximately 60 million inhabitants, comprising numerous ethnicities and dialects. The government recognizes 135 ethnic groups, with the Burmese as the majority.

The Mogok area borders the Shan State, which was settled about 1500 years ago. Today, the area hosts numerous ethnic groups. Besides the Burmese and Shan, other important ethnicities in Mogok include the Lissu and the Gurkha, the latter of whom are of Nepalese descent.

	This Lissu woman is attending the morning gem market. Photo by Andy Lucas, ©GIA.
On this trip, we spent almost all our time in Mogok, focusing on gemstones. The authors had previously visited some of the country’s amazing cultural sights, such as the Shwedagon Pagoda on top of Singuttara Hill in Yangon. Gilded with gold plates, it provides one of the world’s most intense sightseeing experiences.

	The Shwedagon Pagoda is an amazing sight. In addition to being covered in gold, the
	upper areas contain thousands of gemstones, with a 76-carat diamond orb at the top.
	Photo by Andy Lucas, ©GIA.
Bagan is one of the most inspiring areas in the world. Located on the banks of the Irrawaddy River, it has the world’s largest and densest concentration of Buddhist temples, pagodas, stupas, and other ruins. Bagan thrived from the 10th-13th centuries. At one time, the area might have had 13,000 temples and stupas. Today, those that remain have a romantic look, weathered by wind and erosion.

One of the best ways to get to Bagan is by taking a boat from Mandalay. This takes the better part of a day, but provides stunning views of temples along the river banks, with nomadic fishermen and villages devoted to making pottery. Also in the Bagan area are workshops where you can observe expert craftsmen creating all types of lacquerware.

	Anyone interested in history, architecture, ruins, or a romantic, exotic location will be captivated by Bagan. Photo by Andy Lucas, ©GIA.
Buddhism’s influence is felt throughout Myanmar in its temples and pagodas and in the ever-present monks, who are often seen walking barefoot. While all the major religions are represented in Myanmar, the majority of the population—an estimated 89 percent—are practicing Buddhists.

	Monks in red robes are seen throughout Myanmar. Photo by Andy Lucas, ©GIA.
At the start of our trip, the authors flew into Mandalay, the second largest city in Myanmar, the economic center of Upper Burma, and the country's last royal capital. It is also home to a thriving jade market, where vendors sell rough jadeite, and fashion and sell finished jadeite and jadeite-set jewelry. There are local dealers, foreign dealers, and tourists, all making their way through the market’s crowded lanes. Restaurants are busy serving customers and workshops are busy fashioning jadeite. It is a noisy place, with deals being made, cooking pots being handled, and jadeite being sawn, carved, and polished.

	The jadeite market in Mandalay is a hustling environment with plenty of dealing in, and fashioning of, jadeite. Photo by Andy Lucas, ©GIA.

	Mogok
From Mandalay, we traveled by van to Mogok with our guide. Jordan is his nickname, inspired by his exceptional height—especially for the Burmese—which inspires comparisons to Michael Jordan.

	This amazing necklace, known as the Fai Dee Red Magic, is composed of untreated rubies from both Mogok and Monghsu, Myanmar. Photo courtesy of Fai Dee.
The trip to Mogok is much easier today than it was in the past. There are two paved roads reaching Mogok. The first was constructed in the early 1990s and takes you from Mandalay to Mogok in about six hours. The other road was finished fairly recently and allows you to bypass the drive through Mandalay to arrive a couple of hours earlier.

Mogok is about 200 km northeast of Mandalay. It is part of the Kathe district of the Mandalay region, in an area often referred to as Upper Burma. The famous gem-producing area called the Mogok Stone Tract is actually made up of several valleys and their towns. The main ones are Mogok and Kyatpyin, but gems are also found in the valleys surrounding the villages of Bernardymo, Chaung Gyi, and Kyauk Pya That; they are also produced in the Kabaing and Kin valleys. Mogok has approximately 300,000 residents and Kyatpyin around 250,000.

Besides ruby, inhabitants also mine sapphire and spinel, along with commercial quantities of other gems, including apatite, scapolite, moonstone, zircon, garnet, iolite, and amethyst. The Tract is also home to rare stones such as painite, hibbonite, and poudretteite, which are found only in Mogok and a few other gem localities. While in the region, the authors visited a lapis lazuli mine at Oo Saung Thaung Mountain. Peridot is mined at Pyaung Gaung in the Bernardmyo area, where phot bought samples from miners.

View Gallery

	Browse through this gallery and see the beauty and mystery of Mogok Valley.

	Mogok History
In 1915, G.F. Kunz reported hearing a legend about how rubies originated in Mogok. The legend goes that around 2,000 years ago a serpent laid three eggs. The first egg bore the King of Bagan, the second egg bore an Emperor of China, and from the third egg came the rubies found in the ruby mines of Mogok.

References to rubies and Burma have been found dating to the sixth century, during the Shan Dynasty. The ruby mines in Mogok were taken over from the Shan by the king of Burma in 1597. Any rubies over a certain size and weight had to be given to the king. It’s said that some larger stones were broken up so they could be sold rather than turned over. This is illustrated by the legend of Daw Nan Kyi.

According to the legend, a miner named Nga Mauk found an amazing ruby. Instead of giving the entire stone to the king, he broke it in half and gave half to the king, for which he was rewarded handsomely. He sold the other half to a Chinese merchant. Later, a Chinese prince requesting protection from the king presented the ruby as a gift to his court. Upon examination, the king felt that something about it looked familiar. When he compared the newly gifted ruby to the one the miner had presented, he saw that they fit together perfectly and realized he had been cheated. The king had the miner and his family burned alive. His wife, Daw Nan Kyi, witnessed this from a hill where she was collecting wood. She then died from a broken heart—broken in half like the ruby.

	This is the view looking down Daw Nan Kyi Hill into the town of Kyatpyin. According to
	legend, Daw Nan Kyi looked upon a similar view as she watched her family burned alive.
	Photo by Andy Lucas, ©GIA.
The story of the Nga Mauk ruby does not end there. In the 1870s, during the reign of King Mindon (1853-1878),  the French and the English were building colonial empires in Asia. A representative of the French visited the Burmese king and asked him how much he would ask to let some French companies mine in Mogok. The Burmese king then showed the Nga Mauk ruby to the Frenchman, asking him how much he would estimate its value to be. The Frenchman, who had never seen such a beautiful gem, said that it would be impossible to assign a value to such an exceptional gem. The Burmese King replied: If you cannot give me an estimate for that stone, how do you expect me to give you an estimate for the mine that produced it? The Frenchman was speechless and departed. Later, the British learned of the French interest in Mogok and Upper Burma, and feared that the French would take over the region and control access to China. Backed by a consortium of London-based gem merchants, they planned an invasion of Burma with one of its main objectives being control of Mogok and its ruby mines.

	A Mogok made gem painting shows King Mindon presenting the Nga Mauk Ruby to a Frenchman around 1870. Photo by Vincent Pardieu, ©GIA.
In 1886, the British succeeded in taking over Upper Burma. By 1889, they had formed Burma Ruby Mines Ltd. With tremendous interest in the company stock, the company received a series of leases, and was generally profitable until World War I. They introduced water cannons, washing plants, and other mechanized mining methods, and actually moved the town of Mogok into alluvial mining. The company did much to promote Burmese rubies in Europe and around the world. There were numerous operational problems, however, including flooding and theft. Also, the introduction of synthetic ruby caused widespread fear and plummeting prices in the marketplace. These problems finally led the company to abandon the mines in 1931.

In the 1950s, French writer and traveler Joseph Kessel visited the mines and was inspired to write the novel, Mogok, the Valley of Rubies. This increased public recognition of Mogok as the homeland of the finest rubies in the world, especially among the French. After Burma Ruby Mines Ltd. departed the region, local mining went back to its former small-scale methods. Although not as productive as large-scale production, they proved to be more cost-effective and sustainable. When the government nationalized the mines in 1969, smuggling became rampant.

By 1990, mining regulations eased, allowing joint ventures. During the authors’ visits to the mining areas, we found numerous joint ventures between private companies and the government, as well as sole private ventures and foreign investment in mines.

	Mogok mining activity includes both private and joint-venture operations. Photo by
	Photo by Andy Lucas, ©GIA.

	The Geology
To view the topography of the Mogok Stone Tract is to witness a true geological spectacle. It is one of the most interesting and diverse gemstone environments in the world, with a wide range of geological events happening in the area.

Among the most striking visuals of the geological environment are the impressive marble pinnacles that are blackened from weathering. These formations are visible throughout the stone tract and can vary tremendously in size. Once the black, weathered surface is removed, the white marble becomes visible. One of the largest of these outcroppings is the one that the temple Kyauk Pyat That sits upon. It is truly amazing to see these temple structures sitting on outcrops of rock called karsts, like something out of the science fiction movie Avatar.

View Gallery

	Open this gallery and learn about marble pinnacles and their significance to Mogok’s terrain and ruby mines.
The karsts result from the weathering of the marble. This weathering process also plays a part in mining at Mogok. Since marble is an intricate component of much of ruby and spinel formation, as well as its host rock, the gems are weathered and transported along with the marble. The gems are then concentrated in gravels that the Burmese call byon. These gem-rich gravels are highly important to economically viable mining. The authors have seen similar karsts in other locations, like the ruby-producing region of Luc Yen, Vietnam, where they are mostly covered by jungle. The impact on the viewer of these impressive outcrops in Mogok, however, is hard to equal.

Ruby and spinel are formed primarily by metamorphic events—the conditions that form mountain ranges—with rocks altered by both regional and local heat and pressure. One such giant earth event occurred when India collided with Asia. The tremendous force of that collision created the Himalaya Mountains and the geological conditions that allowed for the formation of many gemstones, including ruby, sapphire, and spinel.

	This Burmese ruby necklace, scheduled for auction at the Hong Kong Sotheby's show on April 7th, 2014 is expected to yield USD $8.7million. Photo courtesy of Fai Dee.
Ruby and spinel are commonly found in marble. Deposits associated with the collision between Asia and India are found in several locations on all sides of the Himalayan range: In Tajikistan, Afghanistan, and Pakistan on the western side, in Nepal in the center, and in Vietnam and Myanmar on the eastern side. Because their geological origins are very similar, the stones from these deposits share many characteristics. This creates some fascinating challenges for gemologists working on origin determination.

Skeletons of creatures from ancient ocean-associated, lagoon-type environments contributed calcium and carbon to the sediments, forming limestone that was very impure and rich in clay and organic matter. Heat and pressure converted the limestone to marble during the geologically catastrophic collision of India and Asia. During that metamorphic event, fluids rich in salt and carbon dioxide, resulting from evaporation, were also put in motion. The interaction between these fluids and the marble deposits caused reactions that freed elements like aluminum, chromium, magnesium, and vanadium. The combinations crystallized as spinels when magnesium was present; otherwise, rubies formed in the cavities that resulted from the dissolution of the salt from the evaporite beds.

The actual formation process is very complex, but simply stated, the rubies associated with marble-type deposits along the Himalayan chain originated from the remains of some of the first life forms that existed on earth hundreds of millions of years ago. Blue sapphire, on the other hand, is associated with igneous intrusions, and forms from a relationship between the igneous intrusions and the metamorphic rock, called metasomatism.

These geological events illustrate the great complexity and combination of circumstances necessary for gemstone formation. The chance that a fine ruby or other gemstone will form is also dependent on slow cooling and enough time and space for the crystal to grow—rare combinations indeed. @chapter:25