Green Octagonal Fluorite (2) Crystal Raw Minerals Stones Rocks Collecting

Green Fluorite Crystal in octahedral cleavage 30.2 gr - mm 35 x 35 x 35 Raw Minerals Stones Rocks for Collection, only a piece, ad in photo.

Fluorite, also called fluorine or spatofluore, is a very common mineral composed of calcium fluoride.
The name fluorite may derive from the Latin fluere which means to flow, due to the low melting point, or from the English miners of the Middle Ages who called it mineral flower for its beauty.
From it derives the name of fluorine and the phenomenon of fluorescence. It was already used by the Egyptians to build statues, in ancient Greece as a precious stone and by the Romans for the construction of multicolored vases.
Fluorite often forms large, perfect crystals, generally cubic in shape. It has a perfect octahedral cleavage. Sometimes it forms small distinct particles, dispersed in a matrix or sometimes granular masses.
The structure can be described as a face-centered cubic lattice of Ca2 + ions, with all the tetrahedral cavities occupied by F− ions. Fluorine thus has a tetrahedral 4 coordination, calcium with a cubic 8 coordination.
Fluorite is usually found in hydrothermal veins associated with lead, silver and zinc sulphides, in cavities of metamorphic and magmatic rocks rich in silica, in sedimentary rocks, by deposition from waters rich in solutions of volcanic origin. Finally it can be formed by sublimation of volcanic vapors.
It is rarely clear and colorless; it usually exhibits beautiful violet, blue, yellow, green, pink, red, sometimes white, champagne and brown colors.
Some types, when exposed to ultraviolet rays, show a conspicuous phenomenon of fluorescence, a phenomenon that takes its name from the mineral.
Like many minerals, fluorite is not extracted in its pure state. The separation from unusable rocks can take place with the gravimetric method or by flotation.
Fluorite is used in the aluminum production process, in the ceramic and glass industry.
It is the raw material for the preparation of hydrofluoric acid from which the fluorine is then extracted. In optics it is used for the manufacture of particular lenses and prisms due to its low refractive index. The mineral of particular value is used for the production of ornamental objects.
Important deposits are found in various locations in Italy, Switzerland, Brazil, Norway, Canada, Great Britain, Germany, USA, France, Spain, Russia, Mexico, Morocco, Madagascar, Namibia, Bulgaria.