Manganosite | |
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General | |
Category | Oxide mineral |
Formula (repeating unit) | Manganese oxide, MnO |
IMA symbol | Mng[1] |
Strunz classification | 4.AB.25 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Fm3m |
Unit cell | a = 4.44 Å; Z = 4 |
Identification | |
Color | Emerald-green, becoming black on exposure to air |
Crystal habit | Granular to massive; Octahedral crystals uncommon |
Cleavage | Perfect on [100], [010] and [001] |
Fracture | Fibrous |
Mohs scale hardness | 5–6 |
Luster | Vitreous, adamantine to dull |
Streak | Brown |
Diaphaneity | Transparent to translucent |
Specific gravity | 5.364 |
Optical properties | Isotropic |
Refractive index | n = 2.16–2.17 |
References | [2][3][4][5] |
Manganosite is a rare mineral composed of manganese(II) oxide MnO. It was first described in 1817 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germany.[4] It has also been reported from Langban and Nordmark, Sweden and at Franklin Furnace, New Jersey. It also occurs in Japan, Kyrgyzstan and Burkina Faso.[5]
It occurs in manganese nodules. It also occurs as alteration of manganese minerals such as rhodocrosite during low oxygen metamorphism and metasomatism.[5]