Axinite

Axinite
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General
Category	Mineral
Chemical formula	calcium aluminum boro-silicate, (Ca,Fe,Mn)3Al2BO3Si4O12OH or Ca2(Fe,Mn)Al2BSi4O15(OH)
Identification
Colour	Reddish brown to yellow to colorless. Blue, violet, grey.
Crystal habit	Tabular, wedge shaped crystal
Crystal system	Triclinic
Cleavage	Good
Fracture	Conchoidal
Mohs Scale hardness	6.5-7
Luster	Vitreous
Refractive index	1.68-1.723
Pleochroism	Strong
Streak	White
Specific gravity	3.26-3.41
Fusibility	?
Solubility	?
Major varieties
None

Axinite is a blue, violet-blue, brownish or reddish-brown mineral composed of calcium aluminum boro-silicate, (Ca,Fe,Mn)₃Al₂BO₃Si₄O₁₂OH. Axinite is pyroelectric and piezoelectric