Mineralpedia Details for Fluorite

Named for the composition as bearing fluorite, which in turn receives its name from the Latin ford fluo, meaning “to flow,” in reference to its use in iron smelting to reduce the viscosity of slag. Occurs in a wide range of colors from clear (pure) to most commonly dark to light purple. Uncommonly occurs as light to dark green, yellow, blue (rare) and red (rare). As cleavable, translucent masses to gorgeous cubic and modified cubic crystals micro in size to larger in the centimeter range (1 to 10cm). Usually associated with large Mississippi Valley lead-zinc deposits in Illinois and Kentucky, but also commonly in load vein lead-zince deposits and hydrothermal gold deposits. Alpine cleft deposit as beautiful octahedral red crystals. Fluorite will fluoresce blue, violet, green, yellow, and red, respectively, under ultraviolet light, and can be phosphorescent, thermoluminescent, and triboluminescent.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/fluorite.pdf

Formula

CaF₂ 

Crystal System

Isometric 

Crystal Habit

Crystalline - Coarse, Massive - Granular, Disseminated 

Cleavage

Three perfect, octahedral cleavages. 

Luster

Vitreous (Glassy) 

Color

purple, clear, yellow, green, red, blue 

Streak

white 

Geological Setting

Occurs in a wide range of geologic environments including low temperature Missississippi Valley lead-zinc deposits, hydrothermal gold deposits, Alpine cleft metamorphic environments  

Class

Isometric - Hexoctahedral 

Fracture

Uneven 

Hardness

4 

WebMineral

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Mindat

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Purple to light green cubic crystals from 1 to 5cm with color zoning.

Octahedral crystals to 5mm.

Yellow to golden yellow with purple "inclusions" and crystals to 2cm.

Colorful, classic Fluorite specimen from this now defunct locality. This specimen features yellow to dark purple color zonation and has hundreds of Chalcopyrite micro crystal iclusions.

Special Info

Phillips Collection

Lustrous purple, cubic Fluorite crystals to 1.3cm with showing excellent hoppered growth on the corners of each crystal.

Light to dark purple cubic Fluorite crystals from 1 to 8cm showing hoppered growth and clear corners. Fluorite from Elmwood is almost always associated with Calcite and/or Sphalerite.

Spherical purple Fluorite to 6cm.

Deep green cubic Fluorite with crystals to 3cm on edge.Fluorite from this locality fluoresces a deep purple color.

Fine grained quartz in metamorphic matrix.

Cubic Fluorite to 8mm showing purple zonation along edges and purple cubes to 3mm.

Yellow to golden yellow cubic crystals with reddish-purple zonation onthe crstal edges.

Purple modified cubes of Fluorite to 1.5mm from lower Deadwood Formation.

Clear to light purple Fluorite cubes to 6mm with darker purple internal phantoms along the crystals edges.

Large purple cubes of Fluorite to 3.5cm. Some of the cubes show octahedral faces.

Special Info

Fluorescent

Green Fluorite from a classic locality shows good crystals to 1.5cm and strong blue fluorescence, with a number of crystals showing good penetration twins. 

Special Info

Antique Specimen

This beautiful specimen of Fluorite is accompanied by both a Fred Canfield and US National Museum tags both of which have individual identification numbers matching the numbers on the mineral (see photos). Canfield donated his collection to the Smithsonian (US National) museum and this specimen is most likely one of those specimens. It's not only an excellent antique mineral specimen but a good one at that with composite Fluorite crystals to 7mm with yellow to colorless cores and purple rims. The matrix appears to be a folded mudstone, perhaps the 'killas' mentioned on pages 4 and 107 of Embrey and Symes (1987). Refer to page 107 for a short discussion of these Fluorites probably from Trevaunance mines.

Purple Fluorite, the largest to 5mm, in crevices of limestone lined with light pink Rhodochrosite.

Light yellowish crystalline mass with unidentified black stringers.

Cubic crystals of purple to blue Fluorite showing some color zoning along the edges. Crystal sizes range from 5 to 10mm.

Special Info

Fluorescent

A fine old cabinet specimen with light purple Fluorite crystals to 2cm, several interpenetrating groups. At the base is a 2.5cm cube of Galena and Siderite is seen as brown rosettes over the entire specimen. It sits and displays nicely. There are a few dings but nothing distracting.

Red crystals of Fluorite to nearly 2cm in black Cryolite. The specimen is a cut slab and in some of the photos has been wet to show the crystals better.

Interesting specimen with swirls and bands of dark purple Fluorite and a 8mm Uraninite chunk. 

It is a large cabinet specimen which shows much better in person. The Fluorite crystals  are a light purple and are very glassy and lustrous.

These crystals are actually bluish purple not entirely purple.  It sits naturally with a Sphalerite matrix. It has issues. One of the crystals has two cleaved corners. You can see this in the photos. The larger Fluorite is 2.5cm on edge.

I had to mess with the color in LightRoom as the digital process washed away all the green. Still, it is not correct. Just picture green as in William Wise Fluorite green. On this specimen is a 5mm seam of Fluorite showing no crystals with waterclear Quartz crystals on top. It is a good locality specimen. Hampson collected it in 1984.

The color in the photos show this Fluorite to be purple, but a good portion of it is blue. It is colored zoned from a center of purple to the outer 1cm zone of blue. It is floater piece with no damage. The edges are coated with colorless micro Baryte crystals. The largest crystal is 2.5cm.

A showy beautiful specimen of yellow-orange Fluorite crystals with an outer edge of purple. The largest crystal is 3cm. Very minor knicks and small tiny cleaved areas but you really have to look to see these.

Perfectly water clear Fluorite crystals to 8mm. 

Flourite from the Auglaize quarry is some of the most unique crystals in the world. The Fluorite carries a beautiful goldish brown iridescence and luster. It is typical that specimens also have a few purple crystals like this specimen.

Special Info

Antique Specimen

Interesting light purple Fluorite crystals to 5mm with darker purple corners on each crystal which sit on plates and rosettes of Zinnwaldite. The specimen came from the University of Humboldt at Berlin, Germany. An old inked label has a date of 1892 - see prov. tab.