Fluorite Cubes with Sphalerite

Calcium Fluoride, CaF2
Crystal System: Isometric
Hardness: 4.0
Density: 3.1-3.3

Fluorite is a widespread and common mineral. It often occurs as a primary mineral in veins of which it is the chief constituent, or in the gangue of lead, zinc and silver ores. Fluorite is also found in sedimentary rocks such as limestones and dolomites as well as in igneous rocks such as granites.

Fluorite occurs commonly as cubic, octahedral and dodecahedral crystals in highly variable colors ranging from colorless and completely transparent to yellow, green, blue, purple, pink or black. Crystals may be large and penetration twins are fairly common. Fluorite often fluoresces in ultraviolet light.

More information on the fluorite and mines of Hardin County, Illinois is available.

Zinc Sulfide, ZnS

Sphalerite is a widespread sulfide mineral common to base metal deposits of zinc in which it is formed under a wide range of conditions. It is the most abundant ore mineral of zinc.

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bkeller@rockhounds.com 8/10/95