1. A most common mineral and one of the most common minerals on the face of the Earth: Calcite minerals consist of about four percent by weight of the Earth's crust, and is formed in many different geological environments.

Calcite minerals are used in cements and mortars, in the production of lime, and limestone is used in the steel industry, in the glass industry, as ornamental stone, in chemical and optical uses, and as mineral specimens.
2. Etymology: from Latin calx +? -ite. The name from "chalix", the Greek word for lime.