Fluorite (also called fluor-spar or Blue John) is a mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octohedrons and dodecahedrons are not uncommon.
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2 Uses 3 Details |
Pig carved in fluorite, 5 cm (2 inches) long. |
Octahedral fluorite crystals. |
Blue John
One of the most famous of the older localities of fluorite is Derbyshire, England, where under the name of Derbyshire Blue John beautiful blue fluorite is used for ornamental purposes; its softness, however, has been a bar to general use.
Uses
As well as ornamental uses, fluorite is also used as a flux in the manufacture of steel, in the making of opalescent glass, enamels for cooking utensils, and for hydrofluoric acid. The name fluorite is derived from the Latin fluo, flow, in reference to its use as a flux.
Crystallographic system | Cubic |
Colours | White or colorless, blue, blue-green, yellow, brownish-yellow, or red.* |
Lustre | Vitreous |
Hardness | 4 |
Refractive index | 1.433-1.435 |
Specific gravity | 3.18 |
Cleavage | 1 (octahedral) |
Pleochroism | None |
See also: List of minerals