VS
Name
—
Na₂(Mg₃Al₂)Si₈O₂₂(OH)₂
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Monoclinic
Crystal system
—
6–6.5
Mohs hardness
—
3.08–3.22
Specific gravity
—
Blue-gray
Streak
—
Vitreous to pearly
Luster
—
Perfect on {110}, intersecting at ~56° and ~124°; partings on {010}, {001}
Cleavage
—
C2/m
Space group
—
Amphibole
Structural group
—
Gln · Approved
IMA
—
1845
Named in
—
Blue, Gray, Black
Typical colors
—
Na · Mg · Al · Si · O · H
Elements
—