Calcite Data

The calcite group of minerals includes calcite, magnesite, siderite, rhodochrosite, smithsonite, and the high-pressure polymorph aragonite. Calcite is the primary mineral in limestone, chalk and marble, and forms the stalagtites and stalagmites in caves.

Pronunciation: CAL•site (accent on capitalized syllable)

Color: highly variable to colorless

Luster: vitreous

Diaphaneity: transparent to translucent; may appear opaque in hand specimen

Hardness: 3

Specific gravity: 2.71

Cleavage/fracture: 3 at oblique angles to one another, forming a "squashed box"

Other distinguishing properties: Calcite effervesces (fizzes) easily in dilute hydrochloric acid (or vinegar). Its cleavage rhombs look like "squashed boxes."

Specimen Pictures


Klein, C., and Hurlbut, C.S., Jr., 1999, Manual of Mineralogy (after James D. Dana) [21st edition, revised]: New York, John Wiley & Sons, 682 p.

Los Angeles County Museum of Natural History, The Photo Atlas of Minerals:

Return to the Minerals page.

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