A large hand-sized dioptase specimen of SOLID dioptase. It consists of dioptase that filled in natural cavities in the rock, so thickly the reverse casts stuck and formed one solid dioptase specimen when the rock was removed. In this mass, there is a long cavity, in which free crystals grow to 1.3 cm. On the edge of the cavity, there is another pocket of crystals facing out, which features one 2-cm-long, doubly-terminated crystal. Ex. Charlie Key Collection.