What is Manganite?
Manganite has a serious ore-mineral presence: dark striated crystals can look almost metallic while preserving a record of hot fluids and manganese concentration. Sharp specimens from classic European localities are especially effective in a systematic cabinet.
Mineralogy and crystal structure
Reference formula: MnO(OH). Manganite is a monoclinic manganese oxyhydroxide and an important ore mineral in manganese-rich systems. Its dark colour, metallic sheen and striated prisms distinguish it from softer black manganese oxides, although weathered surfaces can be misleading. Manganite is classified with oxides and has a monoclinic crystal system. Typical hardness is 4–4.5 on the Mohs scale and specific gravity is approximately 4.2–4.4.
Colour, lustre and habit
Typical colours include dark grey, black, steel-grey. The usual prismatic, fibrous, massive habit and metallic, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Manganite forms in or is associated with low-temperature hydrothermal veins, metamorphosed manganese deposits and oxidation zones. Important documented localities include Germany, Brazil, South Africa, India, Japan and the United States.
Steel-grey prisms from a manganese vein
Manganite has a serious ore-mineral presence: dark striated crystals can look almost metallic while preserving a record of hot fluids and manganese concentration. Sharp specimens from classic European localities are especially effective in a systematic cabinet.
Collecting and care
Protect lustrous faces from abrasion and moisture; avoid acids and dust from broken material.
