Images
Formula: MnO
Simple oxide, periclase group,
manganese-bearing mineral
Crystal System: Isometric
Specific gravity: 5.364 measured, 5.36 calculated
Hardness: 5½
Streak: Brown
Colour: Emerald-green, darkening on exposure to black
Solubility: Dissolves with difficulty in strong hydrochloric or nitric acid to a colourless solution
(Dana)
Environments:
Manganosite occurs in metamorphosed manganese deposits as an
alteration product of
rhodochrosite or other manganese
minerals, formed during oxygen-deficient metamorphism of manganese-bearing
deposits. It also occurs in marine manganese nodules
(HOM).
At Långban, Sweden, manganosite is associated with pyrochroite,
manganite and dolomite.
At Nordmark, Sweden, manganosite is associated with pyrochroite,
hausmannite, periclase,
garnet
and dolomite.
At Franklin, New Jersey, USA, manganosite is associated with franklinite,
willemite, calcite
and zincite.
Alteration
manganosite and O2 to hausmannite
6MnO + O2 ⇌ 2Mn2+Mn3+2O4
Increasing temperature favours the forward reaction
AM80.571.
manganosite and quartz to rhodonite
MnO + SiO2 ⇌ Mn2+SiO3
AM80.561
manganosite and quartz to tephroite
2MnO + SiO2 ⇌ Mn2+2SiO4
AM80.571
manganosite and rhodonite to tephroite
MnO + Mn2+SiO3 ⇌ Mn2+2SiO4
AM80.571
rhodochrosite to manganosite and CO2
MnCO3 ⇌ MnO + CO2
Increasing temperature favours the forward reaction
AM80.571.
Back to Minerals