Identification: The mineral calcite, which makes up limestone, is composed of calcium carbonate(CaCO3 ). It varies in color from white to colorless to shades of yellow, orange or gray. Calcite has a hardness of 3.0, a specific gravity of 2.7, and a white or colorless streak. It breaks up readily into crystalline forms called rhombohedrons and can be identified further by its effervescence in cold dilute hydrochloric acid.

Occurrence: Calcite, though of common occurrence in Florida, is a very interesting mineral, found in a variety of forms. In limestone quarries calcite can be found occurring massively or as long needle-like and block-shaped crystals within open cavities or seams in the limestone. In natural solution caves, such as the Marianna Caverns, calcite is often found forming stalactites or stalagmites, and more rarely "cave flowers". As the principal mineral in sea shells calcite is found in both recent and fossil marine and fresh water animal remains.