What is fluorite?

Fluorite is a mineral. Its main constituent is calcium fluoride (CaF₂).
Naturally occurring fluorite looks beautiful as it can contain impurities that give it different colors like green, purple, or pink. It is also a popular power crystal and is known as the “Genius Stone”. Since the ancient times, it has been indispensable as a flux in metal refinement.

The origins of the name “fluorite”

Also known as “fluorspar”, the English name “fluorite” is derived from the Latin word “fluere”, which means “flow”, a reference to the mineral’s use as a flux in iron smelting and ceramics. The element “fluorine”, which is a key constituent of fluorite, also takes its name from this important mineral.

The fascinating properties of fluorite

Fluorite glows when it is heated, which is why its Japanese name is hotaru-ishi, which means “firefly stone”. But besides that, it has a few other interesting properties.

1. Fluorite produces octahedral fragments

The atoms and molecules of fluorite are spatially laid out in a repetitive pattern, in a structure called a cubic crystal system (cubic motif). It has clear cleavage planes, so if you break a fluorite crystal along a specific direction, you will get eight-sided (octahedral) fragments.