May 2008 Mineral of the Month 'Fluorite'

May 2008 Mineral of the Month
Fluorite

From the Latin word ‘fluere” meaning ‘to flow’. The crystals formed by this mineral are cubic and octahedral in shape and are often twinned. Fluorite may also form in massive, granular and compact habits. It occurs in a great variety of colors, ranging from purple, green, colorless, white and yellow to pink, red, blue and even black. Fluorite forms in hydrothermal veins, especially those containing lead and zinc and also around hot springs. Fluorite is a fairly common mineral found all over the world and is associated with quartz, calcite, dolomite, galena, pyrite, chalcopyrite, sphalerite, barite, and various other hydrothermal-vein minerals. As its name suggests, it can be highly fluorescent in ultraviolet light.

Its chemical properties are as follows:

Mineral Group.....................Halides
Chemical formula..............CaF2
Specific Gravity..................3.1 to 3.3
Tenacity…………………...Brittle
Color.....................................Multiple
Hardness.............................4
Luster...................................Vitreous
Transparency....................Transparent to Translucent
Streak..................................White
Cleavage.............................Perfect Octahedral
Fracture...............................Conchoidal