Description
Galaxite, also known as "manganese spinel," is an isometric mineral belonging to the spinel oxide group with the ideal chemical formula Mn2 + Al2O4. Galaxite is the manganese (Mn)-rich endmember of the aluminum (Al) series of the spinel group. Divalent iron (Fe) and magnesium (Mg) readily substitute for manganese in the crystal structure. Trivalent iron can also substitute for aluminum. Therefore, from most natural specimens, the formula is better represented as (Mn, Fe2+, Mg)(Al, Fe3+)2O4. Galaxite generally occurs as small, granular aggregates with a reddish-brown hue. It has a vitreous luster and leaves a brownish-red streak. It is rated 7.5 on the Mohs scale. It was first described in 1932 for its occurrence on Bald Knob, Alleghany County, North Carolina, near its namesake, the town of Galax, Virginia, named after the galax plant. or wandflower that grows in the area. It occurs in carbonate-rich metamorphosed manganese deposits. It occurs associated with alleghanyite, rhodonite, sonolite, spessartine, tephroite, kutnohorite, manganese humite, jacobsite, kellyite, and alabandite in the Bald Knob area. Associated minerals include katoptrite, magnetite, manganese stibite, magnussonite, tephroite, manganese humite, and manganese in the Brattfors mining area of Nordmark, Värmland, Sweden. It is sometimes used as a gemstone.
