Fluorite

Fluorite – CaF2
Elements: Calcium, Fluorine
Class: Halides
Crystal System: Cubic
Hardness: 4
Fluorite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Origin: Huanggang Inner Mongolia – China
Did you know?

Fluorite gave fluorescence its name. In 1852 the physicist George Stokes, studying the mineral's glow under invisible light, coined the word for the whole phenomenon after the stone itself.