| Name: Pyrolusite |
Origin of name: from Greek pyr - meaning fire, and lousis - meaning washing |
Chemical composition: MnO2 |
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Pyrolusite is an oxide of manganese which precipitates in bogs and lakes and on the deep ocean floor; manganese-rich nodules are estimated to cover between 20 and 50% of the area of the floor of the Pacific ocean. Pyrolusite also forms as a secondary mineral by oxidation of other manganese-rich minerals. When it grows in cracks in rock., pyrolusite forms delicate dendritic crusts, as pictured here.
Pyrolusite is one of the main ores of manganese.The origin of its name reflects its use in the glass-making industry, where it is used to decolourise molten glass. The main use of pyrolusite is in the production of ferro-manganese, a raw material for the metallurgical and chemical industries. |
Crystal system: tetragonal |
| Class: Oxides |
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| Hardness: 2.0-6.5 |
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| Cleavage: perfect |
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| Colour: dark grey to black |
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| Specific gravity: 5.06 |