Chemistry - Axinite

Axinite
Image required
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