Fluorite 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.
Many samples
of fluorite fluoresce under ultra-violet light, a property that takes its name
from fluorite. Many minerals, as well as other substances, fluoresce. The
fluorescence of fluorite may be due to impurities such as yttrium or organic
matter in the crystal lattice.
The mineral
crystallizes in the isometric octahedral
system. The Mohs hardness is 4 and the specific gravity is 3.18. Refractive
index values are nω = 1.433 - 1.435.
Fluorite is
used instead of glass in some high performance telescopes and camera lens
elements.
