Galaxite

galaxite

jacobsite

spinel

alleghanyite

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Formula: Mn²⁺Al₂O₄
Multiple oxide, spinel subgroup, manganese-bearing mineral
Crystal System: Isometric
Specific gravity: 4.03 calculated
Hardness: 7½
Streak: Red-brown
Colour: Black or mahogany red
Environments:

Metamorphic environments

At the type locality, the Bald Knob deposit, Bald Knob, Sparta, Alleghany county, North Carolina, USA, galaxite occurs in carbonate-rich, silica undersaturated parts of a metamorphosed manganese deposit (Webmin). It is commonly intergrown with alleghanyite, and further associated with tephroite, quartz, magnetite and jacobsite (AM17.1-18). The minerals here have formed under amphibolite facies metamorphic conditions (AM68.449).

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