MALACHITE with CHRYSOCALLA (small cabinet)

Malachite, a copper carbonate hydroxide mineral with the formula Cu2CO3(OH)2, is known for its opaque, green-banded appearance. It crystallizes in the monoclinic system, typically forming botryoidal, fibrous, or stalagmitic masses in fractures and spaces deep underground, where chemical precipitation is facilitated by the water table and hydrothermal fluids. While individual crystals are uncommon, they do appear as slender to acicular prisms. Occasionally, malachite also forms  pseudomorphs after the more tabular or blocky azurite crystals.

Chrysocolla is the mineral associated with this specimen. It is a hydrous copper phyllosilicate mineral and mineraloid. The structure of Chrysocolla has been under scrutiny, as spectrographic studies from 2006 suggest that materials identified as Chrysocolla may actually be a combination of the copper hydroxide spertiniite and chalcedony. Chrysocolla is typically found in amorphous forms.

This specimen is from our collection and acquired mid 1980s. This kind of specimen is hard to get to, as the mine is no longer operational.