Fluorite | ©Viamineralia
Eastgate Quarry, Weardale, Durham, UK.
Fluorite is constituted by calcium fluoride. It naturally occurs in all colors of the spectrum. The colors may be very intense and almost electric. Pure Fluorite is colorless; the color variations are caused by various impurities, and may be white, purple, blue, red, pink, orange, yellow, brown, green, gray, and black. May also be multicolored and banded.
The crystal forms are most commonly octahedral and cubic; seldom dodecahedral. Crystals may also be a combination of octahedra and cubes, and dodecahedral growths may also be present, forming complex and interesting crystals.
Fluorite from this region is known by its great daylight-fluorescence. Under artificial light it is dark grey-blue and green but switches green and intense blue-violet under daylight (as in the photos).
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