Colored Stone Mining and Distribution
Unlike diamonds which are controlled by a few major mining companies colored stone prices are predominantly influenced by free market conditions. Colored stone deposits are usually worked by small scale independent miners. Production costs are relatively inexpensive compared to the tens or even hundreds of millions of dollars that can be invested into a diamond mine during its production life. Colored stone miners often sell their rough in markets that are visited by international cutters. The price will be negotiated based on supply and demand.
Recently, producing nations have become increasingly aware of the value of their mineral wealth and are exerting more influence over its production. More governments are joining in partnership with the private sector in exploration and mining. The aim is for a greater percentage of the mineral wealth to benefit the host nations. Traditionally, gem rough was either seriously undervalued or smuggled out of countries by dealers aiming to avoid export fees and taxes. As a result, virtually no benefit was derived by the populations living in the host countries.
Gem rough can be mined from both primary and secondary deposits. A primary deposit is one in which the gem crystals are still contained in the host rock. Mining of this type involves pits or tunnels that follow the gem-bearing vein. The gem rough is extradited from the host rock using tools, chemicals, or explosives. Colored stone rough also is mined from secondary deposits. Secondary deposits are areas where the rough has been transported and deposited after being freed from its host rock by natural processes including weathering or erosion.
Unlike the open pit and underground mining associated with the Earth’s largest diamond mines, colored stone deposits are often mined with little more than a shovel, bucket and rope and a kerosene generator to pump air into the tunnel. If the deposit is associated with an active river or stream, mining may consist of shoveling gravel into a pan or sieve where any gem crystals present are extracted by hand. This is an extremely time consuming and laborious process. Once mined, rough gems eventually end up in one of the world’s main cutting centers, for colored stones, usually Thailand, India or China. However, more nations that host gem deposits are investing in the development of cutting centers as a means of adding value to and increasing the benefit derived from their mineral resources. Madagascar and Tanzania are good examples of such nations.