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www.mineralgallery.co.za Minerals P-T |
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Name
Pyrolusite
Chemistry
MnO2 Manganese oxide
Uses
As mineral specimens and as an ore of manganese
Color
The color is black to bluish steel-grey and is always opaque
Hardness
6-6.5
Specific gravity
4.5-7.9
Crystals
It very rarely forms crystals, it is usually found as massive ore. It can form reniform coatings or dendritic plant like shapes on joints or bedding planes in sedimentary rock; also as divergent fibres or columns
Accompanied by:
Hausmanite, hematite and gaudefroyite
Similar to:
Hausmanite
Pyrolusite is a common manganese mineral and forms under oxidizing conditions.
It is often of secondary origin, being found in the oxidation zone of ore deposits containing manganese, and in shallow marine sediments,
It occurs also in quartz veins, and as noddules at the bottom of the sea. The name is derived from two Greek words meaning 'fire' and to 'wash.' because it was at one time used to remove the color from glass due to the presence of iron oxide.