VS
Name
—
(Mn²⁺,Ca)₂ₓ(Mn⁴⁺)₁₋ₓO₂·0.7H₂O
Formula
—
Mineral Species
Entry type
—
Oxides & Hydroxides
Chemical class
—
Hexagonal
Crystal system
—
2.5–3
Mohs hardness
—
3.43
Specific gravity
—
Brownish black to dark brown
Streak
—
Submetallic to dull
Luster
—
—
Cleavage
—
—
Space group
—
—
Structural group
—
Tkn · Approved
IMA
—
1970
Named in
—
Steel-gray to black; yellowish gray in reflected light
Typical colors
—
Mn · Ca · O · H
Elements
—