Prismatine

Prismatine is an orthorhombic-dipyramidal mineral containing aluminium, boron, fluorine, hydrogen, iron, magnesium, oxygen, and silicon. It forms a solid solution series with kornerupine.^[4]

Prismatine
General
Category	Sorosilicate
Formula	([ ],Fe,Mg)(Mg,Al,Fe)5Al4Si2(Si,Al)2(B,Si,Al)(O,OH,F)22
IMA symbol	Prm[1]
Strunz classification	9.BJ.50
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Space group	Cmcm
Identification
Color	Yellow brown, green brown, brown green
Specific gravity	3.34
Optical properties	Biaxial (-)
References	[2][3][4]