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World Mining Report - Africa - November/December 2005
By Gordon Austin, Morgan Beard, Mick Elmore, Cara Woudenberg, and Megan Zborowski
World Mining Report 2005 | Africa | Central & South America | North America | Asia | Australia | Eastern Europe | The Middle East
One source of fine gem tourmaline is the area around Walikale, on the eastern end of the country near the Rwandan border. After DRC troops drove Rwandan troops out of the area during a conflict in 2002, gems began to flow out. Dealers estimate that as of late 2004, approximately 20 to 30 kilograms of fine blue to green tourmaline were coming out of the country, although not necessarily all from the area around Walikale. Most of the material is green, although some is blue-green, yellow-green, or bright pink. The rough will cut into stones of up to three to five carats.
The country is also said to be a source of limited quantities of very fine red andesine, a type of feldspar, but no specifics were available on locality or production.
The John Saul Mine, which produces the bulk of Kenya's annual ruby exports, continues to produce steadily. There are some other major ruby mining operations in the area around Tsavo National Park, although they generally produce cabochon-grade material.
Another exciting find, discovered in late 2004, is a color-change garnet that is said to resemble fine alexandrite, going from blue or green in daylight to pink or red in incandescent light. The deposit is located near Taita Taveta, Coast province. Production is not extensive -- less than a kilogram per month -- but promises to be steady.
Prospects are looking up for a signature Kenyan gemstone, tsavorite garnet. At the biggest single producer, the Scorpion Mine, some new pockets have opened up that are pushing production higher than it has been at any time this decade, approximately three to four kilograms a month of mixed-grade material.
Also from the Taita Taveta area is a steady production of golden tourmaline. The color ranges from the highly sought-after bright yellow to a darker yellow-green or yellow-brown. The region tends to produce large stones, typically in the one to six carat range, and sometimes as large as 10 or 20 carats. Average production ranges from three to six kilograms per month.
Kenya also produces amethyst, iolite, aquamarine, and various species of garnet. At press time, there were rumors of a new find of aquamarine, but nothing had been confirmed.
The ruby deposit at Andilamena, in the northeastern part of the country, yielded a new find in March 2005. The new material is a very rich pink, sometimes edging over the boundary into pink sapphire, and without a lot of inclusions.
Vatomandry, the other major ruby deposit discovered in 2000, is still producing very small rough. Most of this material has a strong purple component that will turn red with heat treatment. The colors from this deposit are gradually improving, but it produces little rough that will cut more than a 1.5-carat stone.
In the north, fancy-color sapphire is still coming out of Diego Suarez. The area is producing more large, blue sapphire in the two- to seven-carat range than before, but tends to have a lot of green.
A pink tourmaline mine just opened near Antsirabe, and while it is not yet producing significant quantities, early reports say the color is deep rubellite pink and the rough will cut clean stones up to three carats.
Another new mine in Vangainrano is producing fine aquamarine and green beryl in sizes from three to 70 carats.
Pezzottaite, a pink beryl that has the distinction of being the newest gemstone to be recognized by the International Mineralogical Association, was discovered near Ambatovita. The initial pocket appears to be mined out, but miners are continuing to work the area and will occasionally find a stone or two.
Chimwadzulu is the single biggest mine in Malawi and is responsible for the bulk of the country's gemstone exports. It's being worked by a private operator, who is currently doing test mapping of the deposit and some mining, amounting to about 4.5 kilograms of facetable material annually. The deposit produces a range of sizes -- generally less than two carats, but larger stones have been found. The color of the corundum goes from a light pink-orange (padparadscha) to pink to deep purple, and can be sold unheated. The material is being marketed in the United States by a single supplier as Nyala ruby.
Another active area is Mzimba, in the northern part of the country near the border with Zambia. Mzimba's main gemstone is aquamarine, but it also produces other types of beryl, as well as garnet, amethyst, and rose quartz.
The major gem-producing areas are in Nampula and Zambezia provinces in the north, which produce aquamarine, tourmaline, amethyst, emerald, morganite, and rose quartz. Official figures for gem production are generally less than 15 kilograms per year for gems of all types; unofficial estimates put the amount in the hundreds of kilograms per year, mostly in aquamarine and tourmaline.
Neu Schwaben, in the Karibib area, produced large quantities of high-quality, blue-green tourmaline in the mid-1990s. It is still thought to have vast reserves, but at last report only about 200 local miners were working the deposits, mostly surface alluvial material. Production has been small and sporadic.
Very fine quality orange spessartite garnet has been found in the Hartmann Mountains, near the Kunene River in the north. The mine is still being worked by a single owner, but produces relatively little.
Also in the south, neighboring Kwara state produces a variety of tourmaline. The shades most often seen on the market are blue and green, although some sites produce yellow-green, pink, and bicolor tourmaline.
In the central part of the country, the Jos Plateau, which covers parts of Plateau, Kaduna, Bauchi, and Nasarawa states, forms a separate geological belt that has been mined for gemstones for many years.
Kaduna and Bauchi states in the north produce blue sapphire in a number of locations, which is usually found in association with zircon. Kaduna also has deposits of aquamarine, morganite, goshenite, and multiple tourmaline mines, mostly producing pink tourmaline. Bauchi, in addition to sapphire, is a significant source of amethyst and white, blue, and yellow topaz.
Nasarawa state produces pink and green tourmaline, aquamarine, emerald, green beryl, and topaz, while Plateau state has aquamarine, almandine and pyrope garnets, and white topaz.
The single gem that's historically gotten the most attention is tanzanite, a blue zoisite whose only known source is the deposit at Merelani, near the city of Arusha in northern Tanzania. The deposit is broken into four blocks, labeled A through D. Block A is mostly inactive. Blocks B and D are mined by small-scale miners, and their output has been gradually declining over the years as the mines get deeper and more difficult to work. Block C is being worked by TanzaniteOne Ltd. (formerly African Gem Resources or AFGEM); the company has set up a mechanized operation that produced nearly 115 kilograms of rough in the first half of 2005.
Also in the northern part of the country, the Manyara area alexandrite and emerald deposits are producing very little at the moment, although there is some active iolite mining nearby. The ruby mines near Longido continue to produce steadily.
The Umba region, which produces ruby, sapphire, rhodolite garnet, and tourmaline, is still being actively mined, but is producing less than it has in the past, in part due to the depth of the mines and miners' limited equipment.
Tanzania was the first place that tsavorite garnet was discovered, in an area called Lemshuko, south of Arusha. The area has both hard-rock and alluvial deposits of tsavorite that continue to produce high-quality material, and recently investors have begun setting up mechanized mining operations in the area. A few miles south of the tsavorite area there are also active rhodolite garnet mines.
Moving to the east of Lemshuko, the ruby mines at Losongonoi are more active than ever. Foreign and local investors have started doing some large-scale mining there for the first time.
In central Tanzania, Morogoro has produced some very exciting finds within the past couple of years. The ones that have gotten the most buzz are the pink and red spinels that are found near Mahenge. The Morogoro region is also host to a new deposit of moonstone, which has produced several hundred kilograms of rough so far.
In the south, near the border with Mozambique, are two of Tanzania's biggest gem deposits, Songea and Tunduru. Songea is known primarily for its ruby and sapphire.
Tunduru produces almost everything, including ruby, sapphire, spinel, garnet, alexandrite, and chrysoberyl. These areas are also producing less than before; they are alluvial deposits, and all of the material that can be easily reached has already been recovered.
In the southeastern corner of the country, the tsavorite mines in Mtwara that made a big splash in the market several years back appear to be mined out.
While emerald is the country's biggest gem export in value terms, amethyst is the biggest export by volume, accounting for an estimated 700 tons of material each year. The bulk of the production is centered in the Mapatizya area near the southern border, which has a single large, mechanized operation and a number of small-scale miners.
The Lundazi area, on the eastern border near Malawi, is best known for its aquamarine. The region is also the source of “canary” tourmaline, a bright yellow tourmaline that has found a huge market in Japan. The region produces several hundred kilograms of aquamarine per year, approximately two kilograms of the canary tourmaline, and some spessartite garnet.
The Mkushi region produces a wide variety of tourmaline, from dark pink rubellite to pink and green bicolored stones to green and dark blue. Local dealers report that new deposits are being discovered constantly.
Zimbabwe also has deposits of aquamarine, chrysoberyl, alexandrite, tourmaline, and yellow, green, and pink beryl.
This report was produced in collaboration with the International Colored Gemstone Association.