Black crystal aggregates of the very rare mineral nsutite (a manganese oxide) from Bihain, Vielsalm, Luxembourg Province, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Nsutite
A tunnel-structured manganese oxide named for Nsuta, Ghana — a common supergene manganese mineral.
Intro adapted from Wikipedia (CC BY-SA).
Nsutite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn²⁺ₓMn⁴⁺₁₋ₓO₂₋₂ₓ(OH)₂ₓ.
It is a member of the Ramsdellite structural group.
Key properties: Mohs hardness 6.5–8.5; specific gravity 4.24–4.67; Metallic to earthy luster.
IMA symbol Nsu, IMA status: approved, named in 1962.
Thought to be supergene, formed under alkaline oxidizing conditions deficient in barium and potassium.
It is found associated with Pyrolusite, cryptomelane, romanèchite, chalcophanite, other Mn oxides, rhodochrosite, quartz, goethite.
The name refers to Nsuta, Ghana, a prominent occurrence.