Chamosite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameChamosite
Chemical Formula(Fe,Mg)5Al(Si3Al)O10(OH)8
Mohs Hardness2
Crystal Systemmonoclinic
Lustervitreous
Streak Colorgreenish white
Cleavageperfect on {001}
Fractureuneven
Specific Gravity3.2
Colorsdark green, blackish green, black, gray
Transparencyopaque
Type LocalityHupei Mine (Qinjiafang Mine), Pingjiang Co., Yueyang Prefecture, Hunan Province, China
Mineral GroupSilicates (Chlorite Group)
Usescollector, geological indicator
Associated Mineralsberyl, emerald
Raritycommon
Description
The image displays a dark, massive to earthy-looking mineral, likely chamosite, serving as a dull, opaque matrix for lighter green emerald crystals. Its color appears to be a very dark green or blackish-green.
Geological Context
Chamosite is an iron-rich chlorite typically found in low-grade metamorphic rocks, hydrothermal alteration zones, and sedimentary iron formations. It forms under reducing conditions and is a common rock-forming mineral.
