Fluorite Value, Price, and Jewelry Information

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A rare pink fluorite specimen with exceptional brightness. 18.56-ct, oval brilliant cut, Chumar Bakhoor, Hunza Valley, Gilgit District, Gilgit-Baltistan (Northern Areas), Pakistan. © Rob Lavinsky, www.iRocks.com. Cropped to show detail. Used with permission.

Although too fragile for most jewelry use, fluorites are often faceted for collectors. They occur in a wide range of attractive colors and can be extremely bright. These gems are also renowned for their fluorescence.

Fluorite Value

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Fluorite Information

Data Value
Name Fluorite
Varieties Blue John
Crystallography Isometric. Usually in good crystals, cubes, octahedra, and other forms, often twinned; also massive, granular.
Refractive Index 1.432-1.434
Colors An extremely wide range is represented: colorless, purple (various shades), green (various shades), blue-green, blue, yellow to orange, brown (various shades), white, pink, red, brownish red, pinkish red, brownish black, black. Crystals are frequently color zoned.
Luster Vitreous
Hardness 4
Fracture Subconchoidal, splintery.
Specific Gravity 3.180; massive material with impurities 3.0-3.25.
Birefringence None
Cleavage Perfect 4 directions. Cleavage is octahedral, very easy.
Dispersion 0.007 (very low)
Luminescence See "Fluorite Properties" below.
Luminescence Present Yes
Luminescence Type Fluorescent, Phosphorescent, UV-Long, X-ray Colors
Enhancements Faceted gems may receive heat treatment or irradiation. Decorative objects may receive coating, dyeing, and plastic impregnation.
Typical Treatments Dyeing, Heat Treatment, Infusion/Impregnation, Irradiation, Surface Coating
Transparency Opaque to transparent
Absorption Spectrum U and rare earths are often present; spectrum reflects their presence. Spectra usually vague, however. Green material has lines at 6340, 6100, 5820, and 4450 and a broad band at 4270.
Phenomena Color change (Very rare)
Formula CaF2
Pleochroism None
Optics Isotropic; = 1.432-1.434.
Etymology From the Latin fluere, “to flow,” because it melts easily and is used as a flux in smelting.
Occurrence In hydrothermal deposits; sedimentary rocks; hot springs; rarely in pegmatites; usually associated with sulfide ore deposits.
Inclusions Mineral crystals, cavities (single, two, and/or three phase), healed fractures.
faceted fluorites

Fluorite: Canada (6.14), Illinois (17.1) // Germany (4.35), Colombia (13.0), New Mexico (1.2), Switzerland (3.5). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Do Fluorites Make Good Jewelry Stones?

Despite its low refractive index (RI), fluorite can take a high polish. This means faceted fluorites can show exceptional brilliance. Many fluorite crystals are also transparent.

Fluorites come in many colors, including colorless. Most available stones occur in shades of purple, blue, or green. Chrome green material from Colombia and pink gems are rare. Lapidaries can cut multi-colored gems (sometimes called “rainbow fluorites”) from color zoned crystals, too.

bi-colored fluorite pendant

Atomic-age inspired sterling silver pendant with a rainbow fluorite stone. Photo by Rhonda. Licensed under CC By-SA 2.0.

Chemical impurities and natural irradiation contribute to fluorite’s colorful varieties. Very rarely, some fluorites display a color change effect, from blue in daylight to purple or lavender in incandescent light. (Materials from England and Cherbadung, Switzerland have demonstrated this).

faceted fluorites 95 - six gems

Fluorite: Colombia (3.05), Switzerland (0.92), Illinois (15.20) // Illinois (5.75), England (6.05), Illinois (8.80). Photo © Joel E. Arem, PhD, FGA. Used with permission.

What is “Blue John” Fluorite?

For over 1,500 years, English artisans used Blue John or Derbyshire Spar as decorative material in vases, carvings, bowls, and so forth. This fluorite variety has bands of white, blue, violet, and reddish brown.

Blue John candelabra

Candelabra with Blue John, circa 1860. Photo by Rauantiques. Licensed under CC By-SA 4.0.

The Derbyshire deposits are nearly exhausted. However, a similar type of fluorite has been discovered in China.

Blue John - slices

A craftsman at the Treak Cliff Cavern workshop in Derbyshire, England placed slices of Blue John, too thin for jewelry, on his window. Photo by Andy Mabbett. Licensed under CC By-SA 3.0. (Cropped to show detail).

Fluorite Properties

Some (but not all) fluorites display fluorescence under ultraviolet light (UV). Thus, confirming the presence of this property isn’t diagnostic for identifying fluorite. However, this property is strongly associated with this gem. In fact, in 1852, the physicist Sir George Gabriel Stokes named this effect “fluorescence” after his studies of the mineral fluorite.

fluorescent green fluorite

Green fluorite crystal under normal light (left) and UV light (right). Photo by GorissM. Licensed under CC By-SA 2.0.

The presence of uranium (U) and rare-earth elements likely cause fluorite’s fluorescence. However, sometimes organic inclusions (hydrocarbons) may be the cause.

Under longwave UV, fluorites can fluoresce yellow, blue, white, reddish, violet, or green.

Some fluorites exhibit phosphorescence under X-rays, a luminescence that lasts even after the light source is removed. Some material is also thermoluminescent, luminescing when heated.

Fluorescent fluorites with a coating of quartz crystals, Allenheads Mine, East Allendale, North Pennines, Northumberland, England, UK. © Rob Lavinsky, www.iRocks.com. Used with permission.

Chlorophane, a rare fluorite variety, shows phosphorescence and thermoluminescence, as well as triboluminescence. It luminesces when rubbed or held in your hand.

chlorophane

Chlorophane under normal light (left) and UV shortwave light (right), Buckwheat dump mineral collecting site, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA. Photo by Modris Baum. Public domain.

Are There Lab-Created Fluorites?

Lab-created fluorite in all its various colors is available. The optics industry especially values fluorite for the creation of high-quality lenses. Its low RI and low dispersion make it an ideal lens material. Not surprisingly, the search for cheaper synthetic production continues apace. Some manufacturers melt and mix high-purity natural fluorites with other materials to create high-quality lenses.

Currently, high production costs, combined with fluorite’s low hardness and perfect cleavage, make synthetics an improbable choice for jewelry.

How Can You Distinguish Fluorites from Other Similar Gemstones?

Due to their considerable color range, you’ll more likely find natural fluorites misidentified or misrepresented as other gems. For example, fluorites have been offered as amethysts, emeralds, and color change garnets.

Hardness testing, of course, is the easiest way to distinguish fluorites from these more popular and durable jewelry stones. However, conduct scratch testing only as a last resort and never on a finished gem. Fortunately, fluorite’s very low RI and dispersion can help distinguish it from many other gems.

One of the more unusual examples of fluorite as a simulant has appeared in Asian markets. So-called “night glowing pearls” aren’t pearls at all but often spherical fluorites, sometimes untreated but sometimes coated with a material to enhance phosphorescence.

Do Fluorites Receive Artificial Enhancements?

Heating to 100-150° C can lighten dark-colored fluorites, but higher temperatures risk removing all color. On the other hand, radiation treatment can turn colorless and pale green material darker blue, green, or purple.

Decorative objects might receive coating, dyeing, and plastic impregnation treatments.

Fluorite Sources

Fluorites occur in many localities worldwide.

faceted fluorites 97 - four gems

Fluorite: Africa (62.55), New Hampshire (152.90), Illinois (17.55), New Hampshire (38.10). Photo © Joel E. Arem, PhD, FGA. Used with permission.

The most well-known sources of gem-quality material include the following:

  • Ontario, Canada: banded, violet material in calcite.
  • Colombia: green.
  • Huanzala, Peru: pink crystals.
  • Chamonix, Switzerland; octahedral pink crystals, on quartz, very rare.
  • United Kingdom: Cornwall; Cumberland; Derbyshire.
  • United States: Colorado; Illinois (occurs in many colors, best known, especially violet material from Rosiclare); Michigan; Missouri (purple, blue, yellow, brown, colorless); Westmoreland, New Hampshire (bright green fluorite in crystals up to 8 inches across); New Mexico.
  • Argentina; Austria; China; Czech Republic; France; Germany; Italy; Korea; Morocco; Myanmar; Namibia; Pakistan; Russia; Slovakia; South Africa.
fluorite - Argentina

Faceted fluorite, Argentina. Photo by Didier Descouens. Licensed under CC By-SA 3.0.

How Large Can Fluorite Gemstones Get?

Since suitable rough from a wide range of localities is available, fluorite crystals can be very large. However, large stones totally free of internal flaws are extremely rare. Thus, cut fluorites suitable for jewelry use are usually small.

faceted fluorite - Illinois

Fluorite: Illinois (1,031 cts, world’s largest of this color). Photo © Joel E. Arem, PhD, FGA. Used with permission.

  • Smithsonian Institution (Washington, DC): 729 (green, Colombia); 492, 354 (pink, Korea); 348 (pale blue, Korea); 263, 234 (light brown, Africa); 118 (purple, England); 354 (pale yellow, Illinois); 229, 124.5 (green, New Hampshire); 117 (green, Africa); 111.2 (violet, Illinois); 118.5, 85.4 (blue, Illinois); 32.7 (colorless, Illinois); 13 (pink, Switzerland).
  • Devonian Group (Calgary, Alberta, Canada): 68 (deep blue, Namibia), 23.7 (pink, Africa); 72.4 (green).
  • Harvard University: 180 (green, New Hampshire).
  • Los Angeles County Museum: 1031 (yellow, triangle, Cave-in-Rock, Illinois, world’s largest yellow fluorite); 100 (chrome fluorite, Colombia); 30 (chrome fluorite, Azusa Canyon, Los Angeles County, California).
  • Private Collection: 100+ (pink, South Africa); 203.5 (yellow, Illinois); 17.92 (brown, Michigan); 3969 (Kashmir-sapphire blue, Illinois).
faceted fluorite - Smithsonian Institution

One of the largest known fluorite gems, 3,965.35 cts, on display at the Smithsonian National Museum of Natural History in Washington, DC. Photo by thisisbossi. Licensed under CC By-SA 2.0.

Is Fluorite Hazardous?

Fluorites contain fluorine (F) as part of their chemical makeup (CaF2). As a gas, fluorine is very toxic. However, fluorites are inert. Wearing or holding fluorite gems or jewelry will pose no health risks. The lapidary processes used to cut fluorites won’t create fluorine gas. (Of course, gem cutters should take basic precautions when working with any gem material).

There are health risks associated with long-term exposure to massive amounts of fluorite in or near mining environments. However, normal gem cutting and handling just won’t result in exposure on that scale.

How to Take Care of Your Fluorite Jewelry

Due to its cleavage, brittleness, and low hardness, fluorite is too fragile for most jewelry use. Ring use isn’t recommended. However, protective settings, occasional wear, and use in pendants and earrings can let you show off these beautiful gems. Some specimens may fade with prolonged exposure to light, so store any fluorite jewelry out of the light. In addition, store them separately from other harder gemstones to prevent contact scratches.

Since fluorites are slightly soluble in water, never submerge them. Clean them only with a warm damp cloth, detergent, and soft brush and never use mechanical cleaning systems. For more cleaning recommendations, consult our gemstone jewelry cleaning guide.

fluorite and sterling silver pendant

Sterling silver necklace with a pear-shaped fluorite. Photo and jewelry by Gaia Metal Studio. Licensed under CC By-ND 2.0.

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