VS
Name
—
Fe²⁺₂Fe³⁺O₂(BO₃)
Formula
—
Mineral Species
Entry type
—
Borates
Chemical class
—
Monoclinic
Crystal system
—
3
Mohs hardness
—
4.28–4.57
Specific gravity
—
Black
Streak
—
Submetallic to vitreous
Luster
—
On {110}, good
Cleavage
—
P2/m
Space group
—
Hulsite
Structural group
—
Hls · Grandfathered
IMA
—
1908
Named in
—
Black with greenish, brownish, or reddish tinge
Typical colors
—
Fe · O · B
Elements
—