VS
Name
—
K₂NaFe²⁺₇(Nb,Ti)₂(Si₄O₁₂)₂O₂(OH)₄(O,F)
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Triclinic
Crystal system
—
—
Mohs hardness
—
3.42
Specific gravity
—
—
Streak
—
—
Luster
—
Perfect on {001}, poor on f0klg
Cleavage
—
P-1
Space group
—
Astrophyllite-Astrophyllite
Structural group
—
Nbp · Approved
IMA
—
1964
Named in
—
Chocolate-brown; in transmitted light, brownish yellow to red-orange
Typical colors
—
K · Na · Fe · Nb · Ti · Si · O · H · F
Elements
—