Fluorite

WHAT IS IT?

  • Chemical composition: calcium fluoride (CaF2)

  • Crystallization: isometric cubic (most common), octahedral & complex isometric (less common)
    (crystal twinning is common)

  • Hardness: 4

  • Impurities produce colorful samples
    Most common colors: purple, blue, green, yellow, colorless
    Less common: pink, red, white, brown,black

  • Formed in hydrothermal veins usually those containing lead and zinc

  • Found in greisens, granites, pegmatites & as a cementing material in sandstones

OTHER FACTS

  • First identified by the geologist J.B. Jukes on the Burin Peninsula (Newfoundland) in 1843

  • Pure fluorite is transparent to visible & uV light

  • The color of fluorites will change when exposed to radiation

  • The element fluorine derived it's name from fluorite (from which it was first produced)

  • Fluorite is the origin of the word "fluorescence".
    In 1852, it was discovered that some fluorites glow when exposed to uV light.

WHERE IS IT FOUND?

  • 230 MT of world reserves with the largest deposits in South Africa (41 MT), Mexico (32 MT) & China (24 MT)

  • The largest producers (annually) are: China (3 MT), Mexico (1 MT), Mongolia (0.45 MT), Russia (0.22 MT),
    South Africa (0.13 MT), Spain (0.12 MT) & Namibia (0.11 MT)

  • The largest single crystal of fluorite was found at Dalnegorsk, Russia and weighs 16 tons & is 7 feet in length

  • In Washington State minor deposits are found in the following counties: Chelan, Ferry, Grant, Lincoln, Okanogan, Skamania, Snohomish,
    Stevens.

WHAT IS IT USED FOR?

  • Ornamental & lapidary uses

  • The Romans used fluorite for carvings

  • Used as a flux for iron smelting

  • Used for manufacturing glass

  • Enameled products

  • Chemical manufacturing (such as hydrofluoric acid - a glass etchant)

  • Microscope & telescope lenses

  • Used to manufacture the lenses in the steppers used for integrated circuit lithography,
    because of it's low light dispersion ( low change in refraction index with wavelength)

  • Used for infrared & uV windows in scientific instruments