Gemstone Mining

Loose Gemstones:

Specials Product:
CODE: D001

Diamond Rough
0.3 - 1.5 carat
USD $ 190/Crt
Detail report
CODE: Z001

Emerald Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: R001

Ruby Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: S001

Sapphire Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE: Y001

Yellow Sapphire Rough
1.5 - 10 carat
USD $ 40/Crt
Detail report
CODE:  C001

Cat Eyes Rough
1.5 - 10 carat
USD $ 30/Crt
Detail report

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Gemstone Mining

Sapphire and Ruby Gemstone Mining in Madagascar
A lot of the excitement in the international gem trade in the last 10 years has come from Madagascar. The size and scope of gem deposits there is still not well understood, but experts believe that Madagascar has some of the richest untapped gemstone resources in the world.
Gem Mining in Tanzania
There is a geological formation in East Africa known as the Neoproterozoic Mozambique Belt. Extending from Kenya southward through Tanzania and Mozambique and the large island of Madagascar, it is thought to contain the world’s richest unexploited deposits of colored gemstones. Gem varieties that have been found there include sapphire, ruby, emerald, spinel, tanzanite, alexandrite, tourmaline, zircon, aquamarine, tsavorite, spessartite, rhodolite and demantoid garnet.
Loose Gemstones From the Mine to the Market
How do loose gemstones get from the mine to the market? Are there a few big buyers who get get first crack at the best stones, leaving the second rate stuff for the rest of us? If you went directly to the mine could you get the best deal on loose rubies or sapphires?
We get asked these sorts of questions on a regular basis. The supply chain for loose colored gemstones is a mystery to many, including many gem dealers who don’t buy or sell rough gemstones. By the time colored gems arrive in America or Europe they may have passed through dozens of hands since the miner dug the material out of the ground, and each pair of hands that touches the gems adds another 20-50% to the final selling price. If you could only cut out some of the middlemen, what a deal you could get!
One reason the supply chain for colored gems is a bit of a mystery is that colored stones, unlike diamonds, are mostly mined by independent, small-scale miners, working in remote locations in far away places such as Sri Lanka, Madagascar, Tanzania, Kenya, Pakistan, Burma, Afghanistan, Columbia and Bolivia. Mining is carried out with pick and shovel, and only rarely with heavy equipment.
In Sri Lanka, for example, there are more than 5,000 registered colored gemstone mining locations on the island. The majority of these pits measure no more than three by three meters, and go down to a maximum depth of 25 meters. Colored gemstone mining is so labor intensive that it is estimated that more than 500,000 people in Madagascar are involved in the gemstone sector, despite the fact that Madagascar became an important gemstone source only in the 1990’s.
Independent miners typically want to turn their hard work into cash as soon as possible. Usually this means taking the rough stone to a local market in the nearest town, or selling the rough to someone who has transportation to the local market.
Mining Sapphire in Australia
The most important sources for sapphire are Burma, Kashmir, Sri Lanka, Madagascar, Thailand and Australia. Though Australia is most famous for opal, they are major exporters of sapphire as well, with much of the production heated and cut in Thailand. As many Australian miners will tell you, much of the sapphire sold as Thai is actually mined in Australia!
A major source of sapphire, and an important industry for the area, is Queensland in Australia’s northeast. In fact sapphire has been mined commercially for more than 100 years on the Anakie field in central Queensland, which also yields gem-quality zircon and, more rarely, diamonds. The sapphires are found in a wide range of colors, including blue, green, yellow, gold, orange, pink, mauve, purple and spectacular multi-colored gems in blue, green and yellow. The most famous of all Queensland sapphires is the 733 ct Black Star of Queensland. Found on Klondyke Ridge in 1935 by 14 year old Roy Spencer, it was allegedly used as a door stop for many years by his father Harry Spencer.
The sapphires are of volcanic origin and occur in alluvial deposits, which are up to 20 meters below the surface. Throughout the ages, sapphires and other heavy minerals were transported and deposited in layers and thus tend to be concentrated in ‘runs’ along particular channels.
Gemstones from Africa
The traditional sources for colored gemstones are in Asia and South America, especially Burma, Sri Lanka and Brazil. But these days Africa is generating most of the the excitement in the gems world. Looking at our own inventory of over 35,000 gems, about 50% of them originate in Africa.
Our business is based in Chanthaburi, Thailand, one of the world centers for cutting and trading colored gemstones. Not surprisingly, Chanthaburi has a significant foreign population. But the foreign population is largely African, not western, as so many African gem traders are active here.
Everyone knows Africa as the source for diamonds, but the colored gemstone business is increasingly important, even though colored gem production is spread across small mines in more than half a dozen countries. The main gemstone producing countries are in southern and eastern Africa, stretching from Namibia in the southwest through Zimbabwe, Mozambique, Malawi and Tanzania to Kenya in eastern Africa. Madagascar, the large island off the coast of Mozambique, is geologically part of this same gemstone-rich area, known as the Neoproterozoic Mozambique Belt.
Colored gemstone production from the African mines is constantly changing and smart buyers have learned to “buy it while you can” since gems that are plentiful one year may hardly be found the next year. This happened with the fine spessartite garnet from Namibia, for example. While there is still some supply from Namibia, it is difficult to find and most of the better spessartite is now coming from Mozambique.
American Gemstones
The United States is one of the main consumers of colored gemstones in the world, but is not known as a important gemstone producer. This was not always the case. Back in the first decade of the 20th century, the US was the leading tourmaline producer in the world, with important mines in Maine and California.
Commercial gemstone mining is still active in 8 different states in the US. Surprisingly, the top state based on total value produced is Tennessee. This is because the American Pearl Company operates the only freshwater pearl farm in the country in Tennessee.
The second most important state in commercial gemstone mining is Arizona, with significant deposits of peridot and turquoise. Arizona is also known for agate, jasper, petrified wood, garnet and opal. Turquoise is the most valuable gemstone produced in Arizona, though production is labor intensive because careful hand extraction is required.
Oregon is internationally famous for its sunstone, a feldspar mineral. Sunstone is a type of labradorite that contains large numbers of microscopic copper platelets that produce an interesting play of color. Oregon also produces a variety of agate, jasper, and obsidian.
Tourmaline was discovered in California at the end of the nineteenth century, and between 1898 and 1914 the Himalaya Mine in San Diego County was the world’s largest producer of tourmaline. Turquoise production also has a long history in California, especially in San Bernardino County, but the deposits are no longer active. There are still tourmaline reserves in California, but the cost of mining tourmaline has become prohibitively high.

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