Calcite Crystals

Dogtooth Spars in Jewel Cave, SD, USA.
Chemical Formula: CaCO3
Color: colorless, white, pink, yellow, or brown.
Diaphaniety: Transparent to translucent to opaque
Hardness: 3 - Calcite
Density: 2,72
Luster: Vitreous (Glassy)
Streak: white
Crystal System: Trigonal - Hexagonal Scalenohedral H-M Symbol (-3 2/m) Space Group: R3_c

Calcite crystals are limestone or calcium carbonate (CaCO3) in its mineral form. All this minerals are called calcium carbonates. There are also magnesium carbonates (MgCO3) but they are not this common. Together those minerals are called carbonates.

There are two possible forms of calcium carbonate: calcite and aragonite. Both have the same chemical formula, but different mineral structure Despite this two main forms, characterized by different crystal structures.

Calcite may be fluorescent or triboluminescent.

Cave formations are neraly always formed by calzite, sometimes by aragonite. All other minerals are rather rare in caves. There are several varieties of calcite relevant for speleologists: