Pyrolusite natural black oxide

Manganese(lV) oxide is the most important ore of manganese from which the metal is mostly manufactured. The oxide occurs in nature as the mineral pyrolusite as heavy gray lumps, or black when powdered. 

Minor applications of natural graphite, quantitywise, exploit its electrical conductivity. Natural graphite, or to an increasing degree mixtures with special conductive carbon black and manganese(IV) oxide (pyrolusite) to increase the electrical conductivity, is utilized in dry cells. It is also utilized in brushes for motors or generators, contact rods, conductive paints and for rendering plastics antistatic. 

The mineral pyrolusite, a naturally occurring manganese oxide, is brovm to black in colour. It is also possible that this may refer to an earth pigment with a high pyrolusite content, such as certain umbers. 

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