Ramsdellite

5 in the gallery

Ramsdellite is a manganese oxide mineral displaying a typically dark, metallic luster and a granular to crystalline habit. When well-formed, it can form compact, opaque crystals that reveal a subtle internal sheen and a steely gray to black color, reflecting its manganese-rich composition. In specimens, ramsdellite often accompanies other manganese oxides and oxide minerals, and is sometimes found in oxidized zones of manganese-rich hydrothermal deposits.

Formula
Mn4+O2
Rarity
Common
Stability
Stable
Collector interest
Moderate Interest
Classification notes
Oxide minerals; MnO2 polymorphs including ramdellite and pyrolusite; rutile-type structure

Where Ramsdellite is found

About Ramsdellite

Notable specimens come from the United States, where high-quality material has been documented. Collectors value ramsdellite for its relative rarity compared to more common manganese oxides, its compact to microcrystalline forms, and the occasional well-formed crystal that shows a durable, metallic surface. While individual crystals may be small, the mineral contributes to understanding manganese oxide chemistries and mineral paragenesis in oxidized zones. Its subdued luster and dark coloration make it a distinctive piece for cabinets focused on oxide minerals and manganese-bearing associations.