Pyrolusite

This rich large-thumbnail specimen from the Errington Pit at the Steeprock Mine, Atikokan, Ontario, features an attractive aggregation of sharp, short prismatic pyrolusite crystals with a striking silvery metallic lustre. Pyrolusite is a manganese oxide mineral best known as an important manganese ore. While it is often quite soft, well-crystallized examples such as this can be surprisingly hard, sometimes harder than glass. Pyrolusite commonly forms as a secondary mineral through the weathering and alteration of other manganese-bearing minerals, and crystallized specimens with this level of sharpness and lustre are especially desirable.

The Steeprock Mine is a classic Canadian locality, historically significant for its iron and manganese mineralization. Pyrolusite specimens from this area are prized by collectors for their robust crystal habit and bright metallic appearance, making this an excellent representative example from an important Ontario deposit.