Calcite has the chemical formula CaCO3 (calcium carbonate) and is one of the most widespread minerals in Slovenia, being a major component of limestone, the most common Slovenian rock.
Calcite can be formed in several ways: by precipitation from cold or warm water solutions, in metamorphic rock, or in the magmatic phase of rock formation. It can also be biogenic in origin. Certain organisms, most notably snails and bivalve molluscs, use tiny crystals of calcite to construct their shells.
Calcite crystals can take on rhombohedral, prismatic, barrel-shaped or scalenohedral forms.