VS
Name
—
NaCa₂Fe²⁺₅(Si₇Al)O₂₂(OH)₂
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Monoclinic
Crystal system
—
5–6
Mohs hardness
—
3.4
Specific gravity
—
—
Streak
—
[Vitreous.]
Luster
—
[Good on {110}, intersecting at ~56° and ~124°; partings on {100}, {001}.]
Cleavage
—
—
Space group
—
Amphibole
Structural group
—
Fed · Approved
IMA
—
1946
Named in
—
Dark green, black
Typical colors
—
Na · Ca · Fe · Si · Al · O · H
Elements
—