Unique, 3.2" Calcite Crystal Cluster on Green Fluorite - China

This is a unique association of yellow calcite crystals that contain a milky grey zone/inclusion, and fluorite crystals. The calcite almost entirely engulfs the fluorite, though fluorite can be found along the edges of the specimen. It comes with an acrylic display stand to assist with presentation. Under long wave UV, this specimen fluoresces two separate colors. The calcite has a faint pinkish-orange fluorescence, while the fluorite fluoresces vibrant purple in color.

Fluorite is a halide mineral comprised of calcium and fluorine, CaF2. The word fluorite is from the Latin fluo-, which means "to flow". In 1852 fluorite gave its name to the phenomenon known as fluorescence, or the property of fluorite to glow a different color depending upon the bandwidth of the ultraviolet light it is exposed to. Fluorite occurs commonly in cubic, octahedral, and dodecahedral crystals in many different colors. These colors range from colorless and completely transparent to yellow, green, blue, purple, pink, or black. Purples and greens tend to be the most common colors seen, and colorless, pink, and black are the rarest.

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.

Fluorite & Calcite
Plate 3.2 x 2.8"