Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005
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Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005 By Thomas R. Yager, W. David Menzie, and Donald W. Olson Open-File Report 2008–1013 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director U.S. Geological Survey, Reston, Virginia: 2008 For product and ordering information: World Wide Web: http://www.usgs.gov/pubprod Telephone: 1-888-ASK-USGS For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment: World Wide Web: http://www.usgs.gov Telephone: 1-888-ASK-USGS Suggested citation: Yager, T.R., Menzie, W.D., and Olson, D. W., 2008, Weight of production of emeralds, rubies, sapphires, and tanzanite from 1995 through 2005: U.S. Geological Survey Open-File Report 2008-1013, 9 p., available only online, http://pubs.usgs.gov/of/2008/1013. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted material contained within this report. ii Contents Introduction ...................................................................................................................................1 Emeralds.......................................................................................................................................2 Rubies...........................................................................................................................................3 Sapphires......................................................................................................................................5 Tanzanite ......................................................................................................................................6 References Cited ..........................................................................................................................7 Tables Table 1. World Emerald Production …………………………………………available in separate file Table 2. World Ruby Production …..…………………………………………available in separate file Table 3. World Sapphire Production ………………………………………...available in separate file Table 4. World Tanzanite Production ……………………………………….available in separate file iii Weight of Production of Emeralds, Rubies, Sapphires, and Tanzanite from 1995 Through 2005 By Thomas R. Yager, W. David Menzie, and Donald W. Olson Introduction U.S. Geological Survey (USGS) historically has not attempted to report comprehensive world production of gemstones on a country basis. This was because estimation of gemstone production is inherently difficult due to the fragmentary nature of the industry, the lack of governmental oversight or reporting in many countries where colored gemstones are mined, and the wide variation in quality between individual gemstones. Unlike diamonds, which, with the exception of the alluvial stones of West Africa, are mainly produced by large international mining companies and evaluated, cut, and marketed through a highly developed pricing structure and complex commercial arrangements, colored gemstones are mainly mined by individuals or small companies and have less developed evaluation and marketing arrangements. The trading centers for colored gems are smaller and less well known than the diamond centers. Colored gemstones, like alluvial diamonds, have the potential to be used to fund civil conflicts and other illegal activities, and because trade in colored gemstones is less organized than that of diamonds, they offer less opportunity for effective regulation of their trade. And, like diamond, until the recent advent of the Kimberley Process no generally accepted estimates of colored gemstone production globally or by producing country have existed. The present paper is a first attempt to develop production statistics for the three precious gems—emeralds, rubies, and sapphires,—and tanzanite, a semi-precious gem. The data consist of the weight of production of each of the gemstones from 1995 through 2005. Preliminary data on the weights of gemstone production were presented as a poster session at the Gemological Institute of America’s Gemological Research Conference in San Diego, CA, in 2006, and as a published abstract (Yager, 2006) in an attempt to gather response to the estimates. The USGS continues to welcome information and suggestions that would improve the data presented here. Information used to make the production estimates presented in this paper include annual USGS Mineral Questionnaires completed by producing countries, data on exports from producing countries, reports from the literature, and company reports. Comparisons of the weight and the value of production of a type of gemstone between countries may differ considerably. Whereas east African countries dominate the weight production of rubies, Burma (Myanmar) is widely thought to have the highest value of ruby production. Data on the value of gemstone production are even more difficult to estimate than is the weight of production. Value of production is dependent upon both the quality and the sizes of the stones produced. Such data are not readily available and are difficult to estimate; therefore this report does not present tables of values of production. Instead, the report briefly discusses the forms in which 1 gemstones are sold, the systems used to value the gemstones, and selected data that illustrate the variability of value of gemstones of a particular type. Emeralds Global emerald production (table 1) increased to about 5,400 kg in 2005 from 4,200 kg in 1995. From 1995 to 2005, Colombia accounted for about 47% of the world’s emerald production by volume; Zambia, about 21%; Brazil, about 20%; Russia, about 7%; and other countries, about 5%. Production shares for individual years are quite variable. Colombia’s emerald production declined to about 1,600 kg in 2002 from 2,500 kg in 1998. Lower production was attributable to a lack of discovery of significant new resources, antiquated mining methods, falling prices resulting from public concerns over enhancement processes, and a global oversupply. Production recovered in 2003 and 2004, but declined again in 2005. In 1998, the Coscuez Mines accounted for 77% of Colombia’s emerald production; the Muzo Mines, 15%; and the Chivor Mines, 8%. In 2005, the La Pita Mines accounted for 60% of output; Coscuez, 20%; Chivor, 10%; and Muzo, 10%. The quality of production declined with the shift to La Pita from Coscuez and Muzo and increasing mine depths (Lau, 1998a; Austin and others, 2005). Emerald production increased in Zambia to 1,860 kg in 2002 from 764 kg in 2001 because of the opening of the Chantete Mine, the expansion of the Grizzly Mine, and the discovery of new deposits in the Musakashi area. By 2004, production had declined to an estimated 1,400 kg because of the shutdown of the Kamakanga Mine and the depletion of the Musakashi deposits discovered in 2002. It is likely that output declined further in 2005 with the closure of the Chantete Mine; the Grizzly and the Kagem Mines accounted for most of Zambia’s remaining emerald production (Laurs, 2004; Gemfields Resources Plc, 2005; p. 15-16; Zwaan and others, 2005, p. 120, 123-124, 126). In Brazil, production declined to less than 500 kilograms per year from 1997 to 1999 from 1,300 kg in 1996 because of lower output from the Santa Terezinha deposit in Goias State. Production increased to 1,100 kg in 2004 and 1,500 kg in 2005 because of higher output from Carnaiba and Socoto in Bahia, the partial recovery of production from Santa Terezinha and the development of mechanized mining in Minas Gerais State. In Minas Gerais, the Belmont Mine expanded and the Piteiras and Rocha Mines were opened in 2001 and 2005, respectively (Austin and others, 2005; Jewellery News Asia, 2006; Departamento Nacional de Producao Mineral, undated). In Russia, the Malyshev Mine was reopened in 2001 by ZAO Zelen-Kamen, which was an Irish-Russian joint venture. From 2001 to 2006, the company produced 3,844 kg of emerald by retreating tailings. Tsar Emerald Corp. of Canada purchased ZAO Zelen-Kamen in 2005 and restarted underground mining operations at Malyshev in October 2006. By October 2007, Tsar Emerald planned to produce at a rate of 600 kilograms of emerald per year (ACA Howe International Ltd., 2007). Other sources of increased emerald production included the Tsa da Glisza emerald project in Canada, the Davdar deposits in China, the Mingora Mine in Pakistan, and the Sandawana Mine in Zimbabwe. Small amounts of emerald were also produced in Afghanistan, Ethiopia, Nigeria, Somalia, Tanzania, and the United States. Data on the value of uncut emerald are very difficult to obtain. Limited data from Colombian Government sources suggests that the average value of low-quality gemstones from Colombia declined to about $0.18 per carat in 2001 from $0.50 per carat in 1996 (Lau, 1998b; 2 Ministerio de Minas y Energia, 2002; Rodriguez, undated; Unidad de Planeacion Minero Energetica, 2006). Although this is probably a reasonable indication of the value of most of the gemstones produced in Colombia, it is certainly not a good indication of the value of individual stones. The value of uncut emerald is dependent upon the color, clarity, and carat weight of individual stones. The clarity can be improved