This Specimen has been sold.
2.6" Calcite Crystals on Calcite - Fluorescent!
This is a beautiful cluster of calcite crystals that formed after larger dogtooth calcite crystals. This specimen was collected from the Fengjiashan Mine in Hubei, China. Under long wave UV, these crystals react by fluorescing orange in color.
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.