In the large and varied garnet family of gemstones, there are six common varieties that are recognized based on their chemical composition: pyrope, almandine, spessartite, grossularite, uvarovite and andradite. There are also some mixed members, such as rhodolite garnet, which is a mixture of pyrope and almandite by composition.
Mali - Africa
New hybrid garnets continue to be discovered. In 1994 a mixture of grossular and andradite garnet was discovered in the West African country of Mali, and was named mali garnet. This discovery drew a lot of interest because the grossular and andradite varieties are among the rarest and most valuable garnets. Members of the grossular group include tsavorite and hessonite. The most famous member of the andradite group is the rare demantoid garnet.
The chemical composition of mali garnet is intermediate between that of grossular (calcium aluminum silicate) and andradite (calcium iron silicate). Though mali garnets are predominantly grossularite, the presence of andradite lends mali an impressive dispersion or fire that is reminiscent of the diamond-like demantoid.
Most mali garnet is mined from alluvial deposits. When the discovery was first made there was a lot of material on the market and prices were moderate. In recent years the supply has diminished and prices have risen. Large sizes are quite rare, so the price per carat tends to increase significantly for larger sizes.
Colors range from yellow, to greenish yellow, to yellowish green, yellowish brown, to brown. Cut stones are notable for their brilliance and especially their dispersion when the body color is light enough to let it show. No enhancements are known in the market.
The most valuable mali garnet is the extremely rare chrome green color. Generally speaking, yellow, greenish yellow and yellowish green stones sell for higher prices than the brownish stones. As with any gem, size, clarity and cut can affect the value significantly, with dispersion being a special value factor for Mali garnets.
- First Published: March-08-2010
- Last Updated: October-08-2010
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