Fluorite

Physical Properties
Chemical formula CaF2
Class Halide
Crystal system Cubic
Habit Cubic
Octahedral
Massive
Granular
Color Colorless
Light green
Blue-green
Yellow
Purple
White (rare)
Brown (rare)
Rose (rare)
Hardness 4
Specific gravity 3.18
Cleavage Perfect octahedral {1111}
Fracture Conchoidal
Splintery
Luster Vitreous
Resinous
Dull
Transparency Transparent to translucent
Streak White
Optical Properties
PPL Usually colorless
May be light purple or green
Low relief
May display octahedral
cleavage
XPL Isotropic
δ None
Twinning Penetration twins common
Special Properties
May fluoresce under UV light
after Perkins, 368-369

Fluorite in Hand Sample

Fluorite hand sample

Subhedral to euhedral light green fluorite

Purple and white fluorite

Scanning electron micrograph of fluorite

Fluorite in Thin Section

Thin section photos courtesy of Alessandro Da Mommio of alexstrekeisen.net.

Colorless fluorite with green amphiboles from Mt. Vesuvius, plane polars
Colorless fluorite with green amphiboles from Mt. Vesuvius, crossed polars

Further Reading

Fluorite at webmineral.com

Fluorite at mindat.org