VS
Name
—
(Mg,Mn)₂(Mn³⁺,Sb⁵⁺)O₂(BO₃)
Formula
—
Mineral Species
Entry type
—
Borates
Chemical class
—
Monoclinic
Crystal system
—
6
Mohs hardness
—
3.88
Specific gravity
—
Brownish gray
Streak
—
Metallic, brilliant on {010}, to pearly
Luster
—
Good on {010}
Cleavage
—
C2/m
Space group
—
—
Structural group
—
Pki · Grandfathered
IMA
—
1890
Named in
—
Black, olive-green, yellowish brown; deep reddish brown in transmitted light
Typical colors
—
Mg · Mn · Sb · O · B
Elements
—