4.7" Dogtooth Spar Calcite Crystal Cluster - China
This is a gorgeous 4.7" wide cluster of dogtooth spar (scalenohedral) calcite crystals that bear wheat-yellow coloration and sharp terminations. It is part of a new find out of the Yunnan Province of China. The base of the matrix has been cut flat, allowing for aesthetic presentation of this mineral without the need for a display stand.
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.