first published in December issue of ICA Gazette
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The greater liberalization of trade in many countries around the world has not only increased the potential markets for gemstone sales around the world, it has als increased the potential for gemstone mining around the world. Prospecting for new gemstone deposits and developing the potential of existing deposits has increased in large countries such as Russia and China, a well as smaller countries such as Madagascar and Tanzania. As a result, the future of gemstone mining is full of promise. Although the economic changes have increased mining costs in some countries, which has led to the closing of mines that were rendered unprofitable, economic develop ment has also allowed greater mechanization and investment of capital, which has made production at many mines more efficient. The 1995 ICA World Gemstone Mining Report, which is organized by country, provides information only on changes in gemstone mining reported during the past three years, not on ongoing operations. Unfortunately, it cannot be comprehensive. The most important recent developments in gemstone mining around the world include the important new ruby deposit at Mong Hsu, Myanmar, which is producing large quantities of vivid red rubies that are now dominating the market, particularly in small sizes and calibrated goods; a promising new sapphire deposit in Madagascar; a huge new chrysoprase deposit in Australia; and a new bright orange spessartite garnet deposit in Namibia.
A large quantity of fine blue sapphire on the market from a deposit in southern Madagascar has created some excitement about the country's gem-producing potential. The alluvial deposit is located in Bekili, near the city of Fort Dauphin. Several thousand miners are involved in working the deposit. The crystal morphology is similar to rough crystals from Kashmir, although the material is cloudy with significant colour zoning. The absorption spectrum is similar to Burma sapphire. Heat treatment is said to be very effective. The colour after heating is a remarkably consistent lively blue. Most of the production is small sizes but a few pieces of several carats have been seen on the market. An iridescent labradorite from Madagascar is being marketed as rainbow moonstone. The material has a slightly grey body colour and dark inclusions but is otherwise similar to the rainbow moonstone from southern India. Madagascar is also producing aquamarine, morganite, emerald, garnets, apatite, and tourmaline. Tourmaline is primarily pink, red, and purple colours. Very large quantities have been produced. The rough appears in sizable boulders which may reach up to 10 kilos each and may contain a mixture of colours from yellow through pink and red t dark brown. Most have inclusions. During the past two years, the amount of emerald produced in Madagascar has decreased considerably.
A new deposit of peridot has been discovered in Ethiopia, north of the Kenya border. The peridot is found near the villages of Magado and Mega within the Mega escarpment about 110 km northeast of Lake Turkana in basalt balls the desert plain. The colour and size is similar to Arizona material. Sizes are usually small. Clean facet grade rough over two grams is rare. Some can be faceted and some is cabochon grade. The Nairobi market now receives a random supply of rough but recently it has increased to sufficient commercial quantities. Further north in Ethiopia, about 100 km from Mega village and about 10 km west of Chumba village, along the road leading to Addis-Ababa, there is also a new locality reported to be producing rhodolite garnets. In 1993, rough opal nodules from Ethiopia began appearing on the market in parcels varying in quantity from a few pieces to several hundred grams. Individual nodules range in size from 20 mm in diameter, to 55 mm in diameter, with a weight of 300 grams. The opal inside the nodules has a body colour ranging from pale yellow to yellow, light orange, orange, reddish brown, light brown, and dark brown. The clarity ranges from transparent to opaque. About 5 percent of the light to dark brown translucent to opaque opal displays play of colour. The second type of opal, about 30 percent of the material, has a yellow, orange, or brown body colour. This type of material is transparent to translucent and shows faint play of colour or no play of colour. This material is very similar to Mexican fire opal. The rest of the material, about 65 percent of the total is opaque and does not show any play of colour and so may be considered common opal or potch.
In northwestern Somalia, between Hargeisa and the coastal town of Barbera, a small village called Mandera is situated in a promising geological environment for gemstones. Finds of beryl family gemstones in the area have recently been reported. Mandera has produced emerald, aquamarine, quartz, amethyst, and pyrope garnet crystals. The emerald is very similar in appearance to African emerald from other localities. Pieces range between 1/4 gram to 4 grams in size. Quality ranges from beryl grade to good cabochon grade and the colour is medium to dark Only a few pieces of aquamarine have been seen. Th quality is good, with clean small pieces less than 1/2 ram.
There is also a new tsavorite locality in Kenya about a thousand kilometer northwest of the previously known localities. The area, which is known as Lokirima, is about 100 km southwest of Lodwar in northwest Kenya close to the border with Uganda. Lokirima is surrounded by three hilly areas known as the Murua Ngithigerr Hills, the Loichangamatak Hills, and the Karasuk Hills. The geological environment is similar to the wellknown tsavorite producing areas of Taita Taveta in southeast Kenya and Lalatema and Merelani in northeast Tanzania. The Lokirima area recently started producing small quantities of tsavorite, lots of a few tens of grams on several occasions. However the tsavorite rough is relatively large in size. A few pieces appearing on the market were up to five grams in size. The Lokirima area has also shown indications of rhodolite garnet and brown zircon. The government of Kenya is developing new legislation to regulate the mining industry in Kenya. The law sets out procedures for exploration licenses, prospecting licenses, mining licenses, and royalties, in addition to licenses for transporting and dealing in controlled minerals, which include gemstones. The proposed Mining and Minerals Act includes employee health and safety regulations and environmental protection and reclamation guidelines and includes provisions for regular inspections to enforce.
A new emerald deposit has been discovered in Manghola, between Lake Evasi and the Ngorongoro Crater in northern Tanzania which shows enormous potential. Substantial production is not expected to be seen on the market until mid-1995. The material produced so far is quite different from the emerald produced at the Manyara deposits in that the colour is a much deeper green and larger crystals, in sizes up to 18 grams, have been produced. In the areas surrounding the Manghola deposit, a few claims are being worked that are producing what may be described as a fine green beryl. As of yet, no substantial quantities have been seen on the market. Another new emerald deposit has been mined at Sumbawanga, west of Lake Rukwa in southwestern Tanzania. Most of the stones are opaque and cabochon material and the quantities are limited. There is a new find of mostly pastel coloured sapphire in the southwest corner of Tanzania in a remote area near the village of Amanimakoro in the Mbinga District of the Ruvuma Region. Ruvuma sapphires range up to 2 grams in size, with the bulk of the production in the 1/4 to 1/2 gram size. The colour is mostly pastel blue with some strong green, magenta, nd red to dark red colours. ther colours are also found, covering the entire spectrum of sapphire.
The Kamakanga emerald mine has reopened and is producing emerald of all grades. The mine was not in full operation for the last seven years. The other emerald mines in Zambia have reduced production considerably. Production of high quality amethyst in two localities has increased. Commercial quality aquamarine and pyrope garnet continue to be produced in considerable quantities in the Lundaze area. There is a new find of dentritic opal, yellow transparent to translucent common opal with tree-like dendrite forms of manganese oxide psilomelane, in southeastern Zambia, 40 km northest of Maamba near Lake Kari.
MOZAMBIQUE
Large quantities of large sized high-quality aquamarine has been produced in the last two ears. Most of the material is naturally blue and does not need to be heated. Some are from the Santa Maria mine and others are produced at different mines in the vicinity. Hundreds of kilos of middle to low quality aquamarines are also being produced. ZIMBABWE The ownership of the Sandawana mine has changed and production ha resumed.
There is a new emerald deposit reported in Northern Transvaal. The deposit is not far from the Gravolette mine. The material seen so far has been commercial quality in various sizes.
A find of bright pure orange spessartite garnet was discovered in Namibia and launched on the world market in February 1993. The colour, which is extremeley consistent from stone to stone, is due to manganese. The new garnet, which is currently being marketed as mandarin garnet, is available in calibrated sizes as well as single stones. Most of the material is clean, although larger sizes have veils which can give some stones a foggy look. The most common inclusions ar small black spots of manganese. The refractive index is 1.80, the hardness is 7 1/4 and the specific gravity is 4.04 to 4.15. Sizes over ten carats are extremely rare. The garnet crystals show the trapezohedron form with 24 natural faces. Production has increased since the launch at the original mine in Kunene. Another deposit of mandarin garnet has been located in the same general area in northern Namibia so production is expected to continue to increase in the near future. Production of fine blue tourmaline has appeared on the market from an older tourmaline mine near Usakos. The colour is very intense, resembling Paraiba tourmaline, but only small sizes are available.
Since the end of the civil war, mineral production is expected to increase in Angola. Aquamarine from Angola has been seen on th market. The rough is large but must be hammered into smaller pieces along the fractures. The colour is pale and most pieces are included. The material is suitable for cabochons or beads.
Nigeria continues to produce aquamarine, tourmaline, sapphire and Nigerian emerald, which is also sometimes called green beryl.
In 1994, a new type of garnet was discovered in Mali. The yellowish green to greenish yellow garnet has a higher refractive index and a higher specific gravity than grossular garnet. It is combination of andradite and spessartite. The colour is similar to chrysoberyl but has more green. The rough is mostly alluvial rounded shapes and crystals up to 5 kilos have been found. Sizes of the cut stones range from melee to 20 carats.Much of the rough is clean.
Large quantities of ruby have been mined in Sierra Leone. The crystals may be large and are often barrel shaped, in sizes up to four inches in length. The ruby is red brown and opaque, suitable only for cutting beads or low quality cabochons. Occasionally, the material can be cut to dislay a star.
The Mong Hsu ruby deposit began producing large quantities of ruby in 1992. Most mining is done by independent miners of the secondary deposits of ruby in the river terraces of the Nam Hsu. The government of Myanmar officially declared the area a gemstone tract in July 1992. There are also government and joint venture mining of the primary occurrence of ruby in the marble in the mountains southeast of the town of Mong Hsu. Rough crystals of Mong Hsu ruby are distinctive in appearance and can be distinguished from ruby mined in the Mogok area due to their unusual growth characteristics. They have well developed crystal habits dominated by prismatic growth on one side and basal on the other. In an unheated state the material has clear colour zoning a blue core which vanishes with heat treatment. The pattern of the zone can still be detected after treatment when examined with immersion. The new Mong Hsu ruby deposit is producing commercial quantities of commercial quality cut in calibrated sizes and also significant quantities of fine quality ruby, particularly in sizes up to a carat. A new deposit of sapphire was discovered near the village of Wai Hpa Fai, near Mong Hkak in the southern Shan States, 75 kilometers east of Mong Hsu. The sapphires are found in an alluvial deposit and are being mined with open pit methods. Most rough is 1.5 cm long but gem qualities tend to be much smaller. Green and blue bicolour sapphires are also found. The traditional mining areas in Myanmar are producing more due to the relaxation of laws governing commercial enterprises in the country. Individuals and companies in Myanmar are now allowed to sell gemstones and jewellery for export at six government-run trade centers in Yangon, Taunggyi, Tachileik, Mandalay, Muse, and Kaw Thaung. Sales at the centers, which opened in May 1994, must be made in foreign currency and are subject to 15 percent tax. Myanma Gems Enterprise issues an official receipt for each sale at the centers which may be used to legally export the gemstones or jewellery.
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