VS
Name
—
NaCa₂(Mg₃Al₂)(Si₅Al₃)O₂₂(OH)₂
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Monoclinic
Crystal system
—
6
Mohs hardness
—
3.3
Specific gravity
—
Very light brown
Streak
—
Vitreous
Luster
—
Perfect on {110}
Cleavage
—
C2/m
Space group
—
Amphibole
Structural group
—
Sdg · Approved
IMA
—
2002
Named in
—
Dark brown to black; in thin section, paler with greater silicon content
Typical colors
—
Na · Ca · Mg · Al · Si · O · H
Elements
—