Axinite represents three minerals:
Axinite-(Fe) Ca2(Fe2+Al2BSi4O15(OH)
Axinite-(Mg) Ca2MgAl2BSi4O15(OH) and
Axinite-(Mn) Ca2(Mn2+Al2BSi4O15(OH)
All of these are sorosilicates (Si2O7 groups) with additional (OH) Specific gravity: 3.3
Hardness: 6½ to 7
Streak: White
Colour: Brown, grey, violet, blue, greenish
Solubility: Insoluble in water, hydrochloric, nitric and sulphuric acid

Plutonic igneous environments
Metamorphic environments

Axinite occurs in cavities in granite, in pegmatites, and in the contact zones surrounding granitic intrusions.

Common impurities for Axinite-(Mg): Ti,V,Mn,Zn,K,H2O;
Common impurities for Axinite-(Mn): Ti,Fe,Mg,Na,K, H2O

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