VS
Name
—
Ca₈Mn³⁺₁₀(SiO₄)₃(Si₃O₁₀)₃(OH)₁₀·4H₂O
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Orthorhombic
Crystal system
—
4.5–5
Mohs hardness
—
3.05–3.33
Specific gravity
—
Brown
Streak
—
Resinous, semimetallic; pitchy to dull when included
Luster
—
Perfect to imperfect on {001}; may be a parting
Cleavage
—
P2mm
Space group
—
—
Structural group
—
Orn · Grandfathered
IMA
—
1921
Named in
—
Light reddish brown, chocolate-brown when enclosing manganese oxides
Typical colors
—
Ca · Mn · Si · O · H
Elements
—