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Download hereGENERAL DESCRIPTION
Fluorite is a calcium fluoride that is common in the hydrothermal deposits of low temperature where it is associated to various sulphides (galena, sphalerite...) and in pegmatitic veins.
The fluorite is a photosensitive mineral, the exposure to sunlight tends to shade the crystal colour. Thus, it is recommended to preserve the samples in the darkness.
It is reactive to the ultraviolet light, its name will give the term "fluorescent". It is a species that is very searched by the collectors for its nearly perfect crystals and the palette of its colours. The majority of the crystallizations appear cubic, sometimes octahedral and more rarely dodecahedral.
The fluorites can be colourless, blue, green, violet, pink, yellow, brown. This diversity of the colours is due to the presence of various elements (such as rare-earth), having more or less undergone irradiations: yttrium, europium, samarium... This colour can unequally be divided into bands, showing crystal growth patterns. The size of the crystals can reach impressive dimensions. The largest crystal was found in New Mexico (USA) with a diameter of 213 cm and a weight of 16 tons.
In France, exceptional fluorites are numerous: the mines of Beix, of Saint Puy Gulmier in Puy de Dôme, of Peyreburne, the mine of Burg in the Tarn, Langeac in Haute-Loire are most known, having produced remarkable samples. The mine of Valzergues (Aveyron) delivered even a crystal of approximately 100 kg. The discovery in the Mont Blanc massif, of octahedral pink-to-red fluorite with associated with smoked quartz are is very praised by collectors. Fluorite is also known in many deposits in the Vosges (Framont, Silbertal, Ste Marie-aux-Mines, Ste Croix-aux-Mines, Raon l’étape, Rémiremont, Val d’Ajol etc), Brittany (La Villeder, Montbelleux, Pontpéan...), in Burgundy where very large deposits are known (Saint-Prix, Voltennes, Romanèche among so much of others), Indre (Chaillac), Givet (Ardennes), Franche-Comté (Faucogney-Saphoz, Plancher-les-Mines, Giromagny), in Paris (with the Forum des Halles !), Durfort (for example of deposit in the Gard), Cabrières (Hérault), Prades, Portalet, Arbouet (the Pyrénées), Kaymar and la Boule (Aveyron), Porres, Fontsante (Var), Montgellafrey and Val Thorens (the Alps).
The type is not definable because this species was already known before the conditions of deposit of the types were defined.
Did you know? It is the principal fluorine ore, it is used in the metallurgy of aluminium and for the manufacture of hydrofluoric acid. Some historical deposits produced splendid crystallizations: Alston-Moor/Weardale in the United Kingdom, Asturies in Spain, Illinois in USA. Numerous Chinese fluorites appeared recently on the market and are varied in shapes and colors.
HISTORY : Name derived from Latin "fluere" meaning flowing, in reference to its melting behavior
Species first described in 1529 by Agricola Georgius (1494-1555), German mineralogist
Type-locality: undefined because species already known from the Ancients
ANCIENT NAME : Spatum vitreum, calx fluorata, spath fluor
CHEMICAL FORMULA : Ca F2
CRYSTAL SYSTEM : Cubic
COLOR : Colorless, white, blue, green, yellow, violet, pink
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous
STREAK : White
MORPHOLOGIE : Well-formed crystals, cubic-shaped, octahedrally-shaped
HARDNESS : 4
CHEMICAL CLASS: 3,18
DENSITY : III - Halogenides
GROUP : Fluorite
STRUNZ CLASS BEFORE 2001 : 3/A.08-10
STRUNZ CLASS AFTER 2001 : 3.AB.25
