This is a stunning small cabinet specimen of the revered emerald-green Dioptase crystals gracing numerous gemmy rhombs of white Calcite from Tsumeb! It's quite a unique piece with unusually isolated Dioptase crystals scattered about relatively large rhombs of translucent to transparent Calcite AND the Calcite overgrows the Dioptase crystals in places, so that they float inside! The larger Dioptase crystals are so luminous with their dark, emerald green color; with the smaller ones gemmy and transparent! The Dioptase crystals vary in size from from 1 mm to 1.2 cm and occur as loners or in loosely clustered groups with all of them showing off very well against the translucent, white Calcite. Calcite rhombs average about 1 cm in size, however, some, like the one at the top of the piece, measures 1.5 cm in maximum dimension! Dioptase is of two distinct generations: the earlier generation of crystals are all small, 1 to 3 mm and nearly all of these are enclosed by the latest generation of transparent Calcite growth on the rhombs, whereas, the larger Dioptase crystals are distinctly part of a later generation and are placed ON the Calcite crystals. An exceptional and truly UNIQUE small cabinet Dioptase and Calcite combo from Tsumeb! Ex. David A. Schorsch collection with label, and before him this was in the first Sussman Tsumeb collection (at the time, the best overall Tsumeb collection around and sold to us in 2003).