Mineral Factbook

Cryptomelane

K(Mn4+7Mn3+)O16IMA symbol: Cmlapproved

Cryptomelane is an oxide or hydroxide mineral with the formula K(Mn4+7Mn3+)O16, crystallizing in the monoclinic system. It has a calculated density of 4.496 g/cm3.

Photos

Cryptomelane specimen photo
Mike Beauregard from Canada · CC BY 2.0 · Commons
Cryptomelane specimen photo
No machine-readable author provided. Kluka assumed (based on copyright claims). · CC BY-SA 3.0 · Commons
Cryptomelane specimen photo
No machine-readable author provided. Kluka assumed (based on copyright claims). · CC BY-SA 3.0 · Commons

Crystallography

Crystal systemmonoclinic crystal systemWikidata (CC0)
Space groupI 4/m
Cell (Å, °)a = 9.832, b = 9.832, c = 2.8648; α = 90, β = 90, γ = 90
Cell volume276.94 ų, Z = 1
Axial ratios1.0000:1:0.2914calculated from COD 1544720
Source structureCOD 1544720 (Mineralogical Journal, 1990) — 1 of 2 structures

Physical properties

Density (calculated)4.496 g/cm³calculated from COD 1544720

Classification

Nickel-Strunz (10th)4.DK.05aWikidata (CC0)
Nickel-Strunz (9th)4.DK.05Wikidata (CC0)