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Fluorite
Current inventory:  3 gems
 

Chemistry:  CaF₂   [Calcium Fluoride]

Discovered in 1529;   IMA status: Valid (pre-IMA; Grandfathered).
The name Fluorite is in reference to its fluorine content. Fluorine gets its name from the Latin word fluere, meaning to flow, because it melts easily and is used as a flux in smelting. The term fluorescence is derived from Fluorite, which will often exhibit this effect.

Classification

Mineral Classification:

Halides

Strunz 8th Ed. ID:

3/A.08-10

Nickel-Strunz 10th Ed. ID:

3.AB.25

3 : HALIDES
A : Simple halides, without H₂O
B : M:X = 1:2

Related to:

Fluorite Series and related compounds

Crystal Data

Crystallography:

Isometric - Hexoctahedral

Crystal Habit:

Cubes, octahedra, rarely dodecahedra, or combinations, with many other forms; rounded or stepped, to 2 m; nodular, botryoidal, rarely columnar or fibrous; granular, massive.

Twinning:

Common on [111], interpenetrant, flattened, also as contact twins.

Physical Properties

Cleavage:

[111] Perfect, [111] Perfect, [111] Perfect

Fracture:

Sub-Conchoidal to Uneven

Tenacity:

Brittle

Moh's Hardness:

4.0

Hardness (Vickers):

VHN₁₀₀=174 - 181 kg/mm²

Density:

3.175 - 3.184 (g/cm³) (3.56 if high in rare-earth elements)

Luminescence:

Fluoresces blue, violet, green, yellow, red under UV; may also be phosphorescent. May be thermoluminescent, or Triboluminescent.

Radioactivity:

Not Radioactive

Other:

Slightly soluble in water (0.016 grams per liter at 18°)

Optical Properties

Color:

Colorless, White, Purple, Blue, Green, Yellow, Orange, Red, Pink, Brown, Bluish Black; commonly zoned

Transparency:

Transparent to Translucent

Luster:

Vitreous, Dull

Refractive Index:

1.432 - 1.448  Isotropic

Birefringence:

0.000 (Isotropic) (Frequently exhibits very weak anomalous birefringence, especially in cleaved, cut or pressed crystals)

Dispersion:

0.007 (very, very low)

Pleochroism:

None

Occurances

Geological Setting:

An accessory mineral in granite, granite pegmatites, syenites; around fumaroles; in carbonatites and alkaline intrusives. Economic deposits in low- to high-temperature hydrothermal veins and stratabound deposits; a cement in sandstones.

Common Associations:

Apatite, Barite, Calcite, Cassiterite, Celestine, Dolomite, Quartz, Scheelite, Sulfides, Topaz, Wolframite

Common Impurities:

Y, Ce, Si, Al, Fe, Mg, Eu, Sm, O, ORG, Cl, TR

Co-type Localities:

Jáchymov (St Joachimsthal), Ostrov, Krušné Hory Mountains, Karlovy Vary Region, Bohemia, Czech Republic; and
Breitenbrunn, Breitenbrunn District, Erzgebirge, Saxony, Germany

Year Discovered:

1529

View mineral photos:

Fluorite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Fluorite is known as the "most colorful mineral in the world." The most common examples of Fluorite are the banded, multi-color gems with various shades of yellows, greens, blues, purples and browns. Fluorite is also available in fine, gem quality solid colors. The most popular of these is deep purple that can rival the best Amethyst colors. Other colors include bright, neon green, blue and a beautiful and very rare near-colorless gem. Color change Fluorite is also available in gems that change from blue to purple-pink or from shades of green to red. Fluorite is too brittle to wear in jewelry because of its easy, perfect octohedral cleavage in four directions. There are many sources of Fluorite crystals in the US and worldwide.
 

  
Fluorite gems for sale: