Fluorite's Crystal Colors

Brown Fluorite
Illinois State Museum Collection

Pure fluorite, composed only of fluorine and calcium, is colorless. The presence of other minerals adds color to the fluorite. White and purple fluorite are common, but it can also be blue, green, yellow, pink, or brown. Its crystal form is usually cubic, and it commonly forms masses of interlocking crystals. It is often associated with other minerals, in crystal-lined pockets or cavities, called vugs. Crystals of Illinois fluorite are highly prized by museums and mineral collectors worldwide.