7.1" Quartz and Calcite Association - Fluorescent

This large specimen contains large calcite crystals coating transparent quartz crystals. The quartz can best be viewed when looking at what could be considered the sides and the bottom of the specimen. Small quartz crystals can be found all along the bottom in a variety of sizes. The largest quartz that can be seen is 2.7" long and nearly flawless.

Under short and long-wave UV lighting, the calcite fluoresces pink-orange.

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. Its fracture is conchoidal, but difficult to obtain.

Silicon Dioxide, also know as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.
Quartz & Calcite
7.1" long, 4.6" wide. Weighs 4 lbs