VS
Name
—
(Ca,K,Na)(Mn²⁺,Fe²⁺)₁₀(Si,Al)₁₆O₃₈(OH)₈·nH₂O
Formula
—
Mineral Species
Entry type
—
Silicates
Chemical class
—
Monoclinic
Crystal system
—
4
Mohs hardness
—
2.83–2.84
Specific gravity
—
—
Streak
—
Resinous
Luster
—
Perfect on {001}; a second prismatic cleavage is noted microscopically
Cleavage
—
A2/a
Space group
—
Stilpnomelane, Clay
Structural group
—
Ban · Approved
IMA
—
1967
Named in
—
Light to dark brown, black
Typical colors
—
Ca · K · Na · Mn · Fe · Si · Al · O · H
Elements
—