Azurite, (w. Malachite)

Mineral: Azurite, Malachite, Quartz
Chemistry: Cu3(CO3)2(OH)2
Size: 105 mm
Owner: Malcolm Southwood
Photographer: Malcolm Southwood

A large (105 mm) crystal of azurite, extensively altered to malachite, with a little quartz-rich matrix attached. 

The specimen is from the so-called “Perkins Sams” pocket, which is believed to have been recovered late in 1980, from deep in the second oxidation zone. The pocket included crystals of two contrasting habits.  Elongated, tapering crystals, of which this is an example, and much more numerous, equant, and composite crystals.

The “Perkins Sams” azurites are characterized by (1) extensive alteration to malachite, (2) association with siliceous breccia fragments, and (3) the development of a layer of electric-blue, secondary azurite at the crystal terminations and at the junction between the original azurite and the replacing malachite.