They are frequently impure , trapping in organic matter such as leaves, twigs, and moss as they accumulate. Because of their impure status, they are classified by some as rocks . Most of these growths are Calcite, but some are crystallized as Aragonite. The environment of formation, however, can be a key guide to whether the mineral crystallized as Calcite or Aragonite. Uses Calcite is the primary ore of calcium.
Calcite is indispensable in the construction industry, forming the base of cement.
Many important chemicals are created from Calcite, as well as useful drugs. It is also crucial in the manufacture of fertilizers, metals, glass, rubber, and paint. The transparent Iceland Spar variety, in which the double refraction is very apparent, was used as Nicol prisms for polarizing microscopes and other optical devices. Calcite forms rocks that are used for ornamental purposes, such as Marble and banded Travertine or Tufa. Calcite is also the main component of Chalk, which is processed as drawing chalk.