Antozonite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameAntozonite
Chemical FormulaCaF2
Mohs Hardness4
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
Cleavageperfect octahedral {111}
Fractureconchoidal
Specific Gravity3.18
Colorsdark purple, black
Transparencymostly opaque
Type LocalityMargnac Mine, Compreignac, Haute-Vienne, Limousin, France
Mineral GroupHalides
Usescollector, scientific-research
Associated Mineralscalcite
Rarityuncommon
Description
This specimen features dark purple to black, granular Antozonite crystals forming a matrix, with several lighter-colored, elongated and blocky crystals of calcite embedded within.
Geological Context
Antozonite is a variety of fluorite that forms in thorium-uranium deposits. Its dark color and characteristic ozone smell upon crushing are due to the formation of fluorine-containing gaseous inclusions caused by natural alpha radiation.
