A druse of tiny calcite crystals nearly completely covers the emerald green dioptase crystals on this specimen from Namibia. It is possible to remove the calcites with nitric acid or weak HCl, but I think the dioptase underneath would be contacted. And it is a handsome piece as is. In person, the dioptase is darker green. Cameras have a hard time rendering the color correctly. A really nice Tsumeb specimen for a reasonable price. 8.5 x 6 x 3.3 cm.