Manganite (MnO(OH)) is a manganese oxyhydroxide and one of the historically important manganese ore minerals. It forms striking dark steel-gray to iron-black columnar crystals with metallic luster, often radiating from a single point in fibrous sprays. The Ilfeld locality in Germany is the type locality and produces the world’s finest crystallized specimens; China has notable Hunan occurrences alongside pyrolusite.
Key Facts
- Mohs hardness 4 — softer than pyrolusite.
- Monoclinic; long prismatic crystals with vertical striations.
- Black to steel-gray with metallic to submetallic luster.
- Brown-black to red-brown streak distinguishes it from pyrolusite (black streak).
- Dehydrates and converts to pyrolusite (MnO₂) over geological time at surface conditions.
Notable Localities
Ilfeld (Germany) is the type locality and produces world-class material. N’Chwaning (South Africa) and Cornwall (UK) yield collector specimens. Hunan and Guangxi host Chinese deposits.
Found at these Localities
- Wessels Mine (韦塞尔斯锰矿)
- Cornwall Mining District (康沃尔矿区)
- Guangxi (广西)
- Hunan (湖南)
