Ron Ringsrud, June 1, 1986
The Coscuez mine, one of a number in Colombia, is rapidly gaining significance as a major source of fine emeralds.
Read MoreK. Schmetzer, H. Bank, June 1, 1981
The higher the chromium content in synthetic emerald overgrowth, the darker the coating and appearance of the stone will be.
Read MorePeter C. Keller, June 1, 1981
A comprehensive review of the history and geology of Colombian emeralds together with descriptions of some of the most famous gems to come from this locality.
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