Calcite

Mineral formula: CaCO₃

Mineral group: the Calcite Group

Crystal system: trigonal

Crystal habit: Over 800 different forms of calcite crystals have been described. Most commonly it occurs as acute rhombohedrons or prismatic with scalenohedral terminations, or combinations of the two.

Cleavage: perfect on {1011}

Fracture: conchoidal

Color: white, colorless, yellow, red, orange, blue, green, etc.

Luster: vitreous, sub-vitreous, resinous, waxy, pearly

Diaphaneity: transparent, translucent

Moh’s scale hardness: 3

Streak: white

Specific gravity: 2.7102

Named after:  Named as a mineral by Gaius Plinius Secundus (Pliny the elder) in 79 from Calx, Latin for Lime

Geological occurrence:  One of the most ubiquitous of minerals, calcite is ound in most geologic settings and as a later forming replacement mineral in most other environments in one form or another. It is most common as massive material in limestones and marbles. It forms as chemical sedimentary deposits as limestone, can be regionally or contact metamorphosed into marbles and rarely forms igneous rocks (carbonatites). Also is a common gangue mineral in hydrothermal deposits.