Fluorite (also called fluorspar) is a mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon.
The word fluorite is derived from the Latin root fluo, meaning “to flow” because the mineral has a relatively low melting point and was used as an important flux in smelting. Fluorite gave its name to its constitutive element fluorine.
Fluorite may occur as a vein deposit, especially with metallic minerals, where it often forms a part of the gangue (the worthless “host-rock” in which valuable minerals occur) and may be associated with galena, sphalerite, barite, quartz, and calcite. It is a common mineral in deposits of hydrothermal origin and has been noted as a primary mineral in granites and other igneous rocks and as a common minor constituent of dolostone and limestone.