Psilomelane
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Mineral NamePsilomelane
Chemical Formula(Ba,H₂O)₂Mn₅O₁₀
Mohs Hardness5
Crystal Systemamorphous
Streak Colorbrownish black to black
Cleavagenone
Fractureuneven to conchoidal
Specific Gravity4.5
Colorsblack, dark gray, yellowish-brown
Transparencyopaque
Type LocalitySolnhofen, Franconia, Bavaria, Germany
Mineral GroupOxides
Usescollector's item, minor ore of manganese
Associated Mineralslimestone, pyrolusite, other manganese oxides
Raritycommon
Description
Intricate, fern-like black dendritic patterns of manganese oxides are beautifully displayed on a light yellowish-brown fine-grained limestone matrix.
Geological Context
These dendrites form when manganese-rich solutions infiltrate microfractures or bedding planes within sedimentary rocks, precipitating as thin, branching mineral growths. The host rock is the famous Jurassic Solnhofen Limestone.
