Translucent sharp crystals of manganaxinite to 2.5 cm in size with some greenish crystals of epidote (4.7 × 3.0 × 3.0 cm). Found from Canta, Lima, Peru — Photo: Ivar Leidus · CC BY-SA 4.0
Axinite-(Mg)
Also known as: Magnesioaxinite.
Axinite-(Mg) is a borosilicate mineral of aluminum, calcium and magnesium of the axinite group, with magnesium as the dominant cation in the place of the structure that can also be occupied by iron and manganese. It was discovered in gem material from Merelani Hills, Lelatema Mts, Manyara Region, Tanzania, which is consequently its type locality. It was initially called magnesioaxinite, referring to its membership in the axinite group and the role of magnesium as the dominant cation. The International Mineralogical Association (IMA) later changed its name to axinite-(Mg).
Intro adapted from Wikipedia (CC BY-SA).
Axinite-(Mg) is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₄Mg₂Al₄[B₂Si₈O₃₀](OH)₂.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Axinite structural group.
Key properties: Mohs hardness 6.5–7; typically brown or yellow or blue; white streak; vitreous luster.
IMA symbol Ax-Mg, IMA status: approved, named in 1975.
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