staurolite
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staurolite |
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| navigate by keyword : are collection crystals geo geologic macroscopically mineral penetration prismatic religion shape staurolite twinning visible |
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| Staurolite is a red brown to black, mostly opaque, nesosilicate mineral with a white streak. It crystallizes in the monoclinic crystal system, has a Mohs hardness of 7 to 7.5 and a rather complex chemical formula: Fe2+2Al9O6(SiO4)4(O,OH)2. Magnesium, zinc and manganese substitute in the iron site and trivalent iron can substitute for aluminium. A special property of staurolite is that it often occurs twinned in a characteristic cross-shape, called penetration twinning. |
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Stockphotos.ro (c) 2025. All stock photos are provided by Dreamstime and are copyrighted by their respective owners. |
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