Aspidolite

Aspidolite is a mica group phyllosilicate mineral, the sodium analogue of the magnesium-rich mineral phlogopite. The ideal chemical formula for aspidolite is NaMg₃AlSi₃O₁₀(OH)₂.^[2]

Aspidolite
General
Category	Phyllosilicate minerals, mica group
Formula	NaMg3AlSi3O10(OH)2
IMA symbol	Asp[1]
Crystal system	Monoclinic
Crystal class	2/m
Space group	C2/m
Unit cell	a = 5.291(8), b = 9.16(2), c = 10.12(2) Å
Identification
Fracture	Micaceous
Optical properties	Biaxial (-)
References	[2]