Pyrolusite

Unknown Owner

An excellent thumbnail specimen for the species and locality with lustrous prismatic crystals of pyrolusite coming off matrix. In good condition.Pyrolusite is a manganese oxide mineral that commonly forms in the oxidized zones of manganese bearing deposits. It typically appears as dark gray to black fibrous or massive material and is an important ore of manganese. Specimens are well known for their quality at this locality, where small mining operations explored iron and manganese bearing deposits in Precambrian rocks of the Upper Peninsula. Although the region was known mainly for iron mining, secondary manganese minerals such as pyrolusite have been found in altered zones of the host rock.