Manganite
Manganite is a manganese oxide mineral with the chemical formula γ-MnO(OH). It is a relatively common mineral found in hydrothermal veins and bog iron deposits, often associated with other manganese oxides like pyrolusite and psilomelane.
Properties:
- Chemical Formula: γ-MnO(OH)
- Crystal System: Orthorhombic
- Color: Steel-gray to black, sometimes brownish-black
- Streak: Dark brown to reddish-brown
- Luster: Metallic to submetallic
- Hardness (Mohs): 4
- Density: 4.2 – 4.4 g/cm³
- Cleavage: Perfect on {010}, good on {110}
- Fracture: Uneven
- Tenacity: Brittle
Occurrence:
Manganite typically forms in low-temperature hydrothermal veins and as a product of weathering in manganese-rich deposits. Notable occurrences include Ilfeld in the Harz Mountains, Germany; Granam, Sweden; Cornwall, England; and various locations in the United States, including Michigan and Nevada. It can also be found in bog iron ores.
Uses:
Manganite is a minor ore of manganese. Manganese is used in the production of steel to improve its strength, hardness, and wear resistance. It is also used in batteries and as a coloring agent in glass and ceramics. While not a primary source of manganese, manganite can contribute to manganese production when present in significant quantities within ore deposits.
Distinguishing Features:
Manganite can be distinguished from other manganese oxides by its orthorhombic crystal structure, good cleavage, and association with other manganese minerals. Its characteristic dark brown streak is also a useful identifying feature. X-ray diffraction analysis can definitively confirm its identity.