Nesosilicate, garnet group, manganese mineral
A complete solid solution exists among calderite, andradite and spessartine.
Specific gravity: 4.08
Colour: Dark reddish brown to dark yellowish, brown-yellow
End member calderite is stable only at high pressure, greater than 22 GPa, and low temperature, and the pure
end member does not occur in nature. Calderitic andradite is found
in high pressure metamorphic
iron and manganese-rich quartzite and
chert, also in metamorphosed manganese-silicate-oxide and
silicate-carbonate rocks, and in areas of subduction zone metamorphism
At the Wabush iron formation, Labrador, Canada (one of two co-type localities), calderite occurs in an iron formation associated with pyrolusite, aegirine, rhodonite, hematite, rhodochrosite, quartz and kutnohorite (HOM).
At Otjosondu, Omatako, Namibia, calderite occurs in a manganese deposit (HOM).
Common impurities: Ti, Mg
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