Fluorite

Very common and often very colourful mineral of the halide class

Fluorite shop

mehrfärbiger fluorit aus argentinien - mulitcoloured fluorite from argentinaLike most minerals the chemically pure form is colourless. Colours are produced by impurities. In the case of Fluorite, these mostly are rare earth minerals like Lanthanum, Samarium an Yttrium. mehrfärbiger fluorit aus argentinien - mulitcoloured fluorite from argentinaLike most minerals the chemically pure form is colourless. Colours are produced by impurities. In the case of Fluorite, these mostly are rare earth minerals like Lanthanum, Samarium an Yttrium.mehrfärbiger fluorit aus argentinien - mulitcoloured fluorite from argentinaLike most minerals the chemically pure form is colourless. Colours are produced by impurities. In the case of Fluorite, these mostly are rare earth minerals like Lanthanum, Samarium an Yttrium.
Multicoloured fluorites from Argentina

Origin of name: from Latin fluere = to flow, because of its use as a flux.
The term fluorescence is also derived from fluorite, because this mineral often very strongly displays the effect.

Synonyms and trade names: a violett/blue and yellow variety of fluorite from Derbyshire, United Kingdom, is known as "Blue John".

Can be confused with: because of the wide range of colours, fluorite can be confused with almost any other gemstone. However, identification by optical and physical data is quite simple and straightforward.

gruener fluorit aus pakistan - green fluorite from pakistangruener fluorit aus pakistan - green fluorite from pakistangruener fluorit aus pakistan - green fluorite from pakistan
Three green fluorites from Pakistan.
The two stones from the left can easily be confused with emerald.

Localities: very common on all continents.


opaker fluorit aus mexiko - opaque fluorite from mexicoopaker fluorit aus mexiko - opaque fluorite from mexico
Opaque fluorites from Mexico
transluzenter fluorit aus mexiko - translucent fluorite from mexicotransluzenter fluorit aus mexiko - translucent fluorite from mexico
Translucent fluorites from Mexiko

fluoritschnitzerei aus indien - fluorite carving from india
Carved fluorite from India

Handling: fluorite has perfect cleavage in three directions and must be set with great care. Do not clean ultrasonically!
Furthermore fluorite is highly susceptible to acids. No borax, no alum and above all no sulphuric acid!!

ATTENTION: produces the highly poisonous hydrogen fluoride if brought into contact with sulphuric acid (e.g. in a rhodium bath). Even smallest concentrations of this gas can cause irritations or burns of the wind-pipe, if inhaled!

Worth knowing: the trade name "Blue John" is probably a corruption (malapropism) of the french bleu et jaune, blue and yellow.
Like with most minerals, the chemically pure form is colourless. Colours are produced by impurities. In the case of fluorite, these mostly are rare earth minerals like lanthanum, samarium an yttrium.

Fluorite shop

Gemmological Properties of Fluorite

Formula:
CaF2
Crystal system:
cubic
Mohs hardness:
4 (reference stone)
Specific gravity:
3.17 to 3.56, average 3.18
Refractive index:
singly refractive 1.443-1.448
Max. Birefringence:
frequently displays anomalous birefringence due to interior strain
Dispersion:
none
Pleochroism:
none
Luminiscence:
usually very strong violetish blue
Lustre:
vitreous, often dull
Cleavage:
perfect
Fracture:
sub-conchoidal to splintery
Colour:
occurs in almost all colours