Pyroxene
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Mineral NamePyroxene
Chemical FormulaXY(Si,Al)2O6 (X=Ca,Na,Fe2+,Mg,Li; Y=Mg,Fe2+,Fe3+,Al,Cr,Ti)
Mohs Hardness5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite to grayish-green
CleavageTwo distinct cleavages at approximately 87° and 93°
Fractureuneven to conchoidal
Specific Gravity3.2
Colorsdark green, black, brown
Transparencytranslucent to opaque
Type LocalityEtna, Italy
Mineral GroupSilicates
Usesindustrial, collector
Associated Mineralsplagioclase, olivine, magnetite
Raritycommon
Description
A pale, blocky pyroxene crystal, appearing somewhat translucent, with internal lines and small inclusions, is visible under plane polarized light. Its distinctive shape, noted to resemble a human face, is set within a dark, fine-grained basaltic matrix.
Geological Context
Pyroxenes are crucial rock-forming minerals, commonly found in mafic and ultramafic igneous rocks like basalt and gabbro, where they crystallize from cooling magma. They also occur in various metamorphic rocks.
