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Mineralpedia Details for Bementite

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Bementite

Bementite

Named for American mineral collector Clarence Sweet Bement. It is an uncommon but widespread mineral that occurs in the United States, England, Sweden, Russia, Japan, and South Africa among several others. Bementite can be found in layers parallel to veins of calcite and intergrown with other manganese minerals. Associated minerals include calcite, willemite, hausmanntie, jacobsite, braunite, alleghanyite, baryte, grossular, johannsenite, rhodochrosite, and inesite.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/bementite.pdf

Formula
Mn7Si6O15(OH)8 
Crystal System
Monoclinic 
Crystal Habit
Massive, Radial 
Cleavage
Perfect, Good, Good 
Luster
Vitreous (Glassy) 
Color
brown, gray, yellow, yellow brown, pink 
Streak
yellow white 
Class
Monoclinic - Prismatic 
Hardness
WebMineral
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Bementite from Gambatesa mine, Reppia, Graveglia Valley, Genova prov., Liguria, Italy

Bementite
            from Gambatesa mine, Reppia, Graveglia Valley, Genova prov., Liguria, Italy

Light pink, thin platy crystals to 0.5mm in open vugs and composing the matrix.

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