Mineral

Composition

% Mn composition

Bementite

Mn₅Si₆O₁₅(OH)₁₀

43.2

Braunite

Mn₂Mn₆SiO₁₂

66.6

Cryptomelane

KMn₅O₁₆

59.8

Franklinite

(Fe, Zn, Mn)O (Fe, Mn)₂O₂

10 - 20

Haussmannite

Mn₃O₄

72.0

Manganite

Mn₂O₃H₂O

62.5

Manganian calcite

(Ca, Mn)CO₃

35.4

Romanechite

Ba MnMn₅O₁₆(OH)₄

51.7

Pyrolusite

MnO₂

63.2

Rhodochrosite

MnCO₃

47.8

Rhodonite

MnSiO₃

41.9

Wad

Hydrous mixture of oxides

Variable