A wonderful and uncommon specimen from the famous Tsumeb Mine! This is a cluster of super-sharp rhombs of calcite, given their beautiful green tone by a myriad of tiny, bright green crystals of dioptase inside! Tsumeb is justly famous for its dioptase, and also produced fine calcite specimens in all sorts of forms. Here you have something truly unusual, and in superb condition. The crystals measure to 1.8 cm along the edge. With a loupe, you can see how the tiny dioptases grew on the calcite surfaces at some point, and then were engulfed when growth of the calcites started up again. Ex. Rob Smith Tsumeb collection.