Fluorite and its history
  

HISTORY    GENERAL INFORMATION    HABITUS    COLOURING    INDUSTRY

 

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The book "Valzergues fluorite mine"
E. Guillou-Gotkovsky
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Gilles Emringer's blue Valzergues fluorite

Yellow-blue s pecimen - Yellow vein - Valzergues fluorite mine
Collection Gilles Emringer.

HISTORY

Fluorite is the most important natural fluoride. It can be found in many veins that are often associated to granitic rocks. Due to its richness and its colors, the fluorite has always been fascinating for the man. This mineral received several names (Spatum vitreum, Calx fluorata...) before being called fluorite. The commercial and industrial word is fluorspar (spathfluor in French...) 

Its crystallographic structure, very simple, was determined by William H. Bragg. This was done by x-rays diffraction.

Blue Fluorite, Cave-in-Rock - USA
Blue Fluorite - Cave-in-Rock - USA
Mont-Blanc pink fluorite
Valzergues fluorite stalactite
Fluorite octahedrons on calcite
Mont-Blanc
Cluster of yellow fluorite cubes, disposed like a stalactite
Valzergues - Yellow Vein


GENERAL INFORMATION :

Chemical class : HALIDES
Crystalline system : CUBIC
Etymology : from Latin « fluere »= to flow - use in metallurgy.
Morphology : cubical, octahedral...
Color : from  colorless to all colors.
Hardness : 4 (Mohs scale)
Index of refraction : n = 1.434
Average density = 3.13
Melting point : 1360 °C
Transparency
: all optical qualities are found (from gem to stone).
Fluorescence : UV (long and short waves).
Solubility : in various acids, and aqueous solutions.
Pseudomorphosis : often quartz.
Use : mainly in metallurgy and chemical industries.
Gitology : formation at low temperature. Especially often found in France.


Fluorite deposits:
-in the form of the principal mineral (see page "Mines of fluorite")
-in the form of a secondary mineral (see page "Other mines")

Valzergues mine is a typical exemple of hydrothermal veins.

Fluorite - Valzergues - Aveyron
Fluorite - Valzergues

A nice specimen from the Yellow Vein (two sides).The color is very interesting (honey-amber)


 

HABITUS

The major part of crystallisations is cubic. Parallelepipedic crystals are less often found.
Octahedral shapes appear when the temperature in which crystallisation can occur is higher.
At last, the fluorite can be in the form of spheres like crystallisations coming from Mahodarry (India)…

Many intermediate shapes can also exist.(hexaoctahedron, tetra hexahedron…etc).

The size of the crystals can reach impressive dimensions and weight  (A 100 kg single crystal was collected in the Valzergues mine - see book page 157)

Twins can also be found (« Cumberland » twins). Epitaxies and pseudomorphosis appear in some mines.

 

COLOURING

El Hammam - Morocco

El Hammam - Morocco

Berbes - Spain

Berbes - Spain

Mina Emilio - Spain

Mina Emilio - Spain

Caravia - Spain

Caravia - Spain

Fluorite from Argbla, Morocco
Fluorite from Argbla, Morocco
Chinese fluorite
Fluorite from Spain
Argbla - Morocco
Argbla - Morocco
China
Spain

 

The colouring is due to the presence of various compounds in the crystal :they can be ions (yttrium, europium…).

The most widespread colors are :

- violet, light purple to dark purple (Berbès …)
- blue (Beix, Burg…)
- pink (Mont-Blanc…)
- yellow (Valzergues)
- green (La Barre…)


Crystallisations can also have an association of colors (for instance :
Valzergues where yellow fluorites have a blue-purple edging).

Heating and light tend to make the colour of the crystals disappear. Consequently, it is recommended to store the samples in darkness.

The notoriety of Valzergues fluorite comes from the rarety of its color.

Fluorite from the "yellow vein" - Valzergues - Aveyron - France
Fluorite from the "yellow vein" - Valzergues - Aveyron - France
Fluorite from the "yellow vein" - Valzergues - Aveyron - France

Amber, purple and deep yellow with blue edge...
Specimens from the "yellow vein" - Valzergues - Aveyron - France

 

Fluorite twins - Rogerley
Rogerley fluorite under sunlight
The Rogerley fluorite is world-known for its dichroism.
Left : artificial lighting
Right : Natural ligh
Photos Jesse Fischer - private coll..

 

INDUSTRY

 

The use of fluorite as an industrial mineral is recent. Until the half of the XIX century, its interest was mainly ornamental. Then, it became industrial in the 1980s. The industrial growth goes back to 1860-1880. Currently, the fluorite is mainly used in the following fields:

Chemical industries (manufacturing of hydrofluoric acid, thermic fluids…)
Iron and steel industries (melting in the blast furnaces…)

…and in fields of less economic importance.

Industries of glass and ceramics
Welding…

Valzergues fluorite was primaly used in iron and steel industries, in various factories located anywhere in France. It was exported to the United States, too.

Share - Spath Fluor French Society

One of the industrials...

 

Fluorite  - Afghanistan
Fluorite rouge - Madagascar
Fluorite bleue - Brésil
Fluorites offered by ©Gemfrance.com

 

Fluorite pictures on Spathfluorminerals & MultiAxes

 


  

 

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E. Guillou-Gotkovsky© 2000-2011
18/12/08