This Specimen has been sold.
1.8" Conichalcite and Calcite Association - Aghbar Mine, Morocco
This is an association of green conichalcite and calcite crystals, collected from the Aghbar Mine in the Drâa-Tafilalet Region of Morocco.
Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.