6.3" Fluorescent Calcite Crystals on Clear Quartz - Peru

This is an incredible formation of rhombohedral calcite crystals on a bed of clear quartz crystals. It comes from the Lima Department of Peru and the entire specimen measures 6.3" wide. The calcite has a faint pink coloration to it, indicating it has trace amounts of manganese impurities. It is also extremely fluorescent under short-wave UV light, exhibiting a vibrant orange fluorescence.

It comes with an acrylic 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.

Quartz is the name given to silicon dioxide (SiO2) and is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich environments--usually igneous rocks or hydrothermal environments like geothermal waters--at temperatures between 100°C and 450°C, and usually under very high pressure. In either case, crystals will precipitate as temperatures cool, just as ice gradually forms when water freezes. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountain formation: these veins can be hundreds of millions of years old.

Calcite & Quartz
Lima Department, Peru
6.3 x 4.2 x 1.8"