VS
Name
—
(Al,Fe)₁.₃(V⁵⁺,V⁴⁺,Fe³⁺)₈O₂₀·7.5H₂O
Formula
—
Mineral Species
Entry type
—
Oxides & Hydroxides
Chemical class
—
Monoclinic
Crystal system
—
3
Mohs hardness
—
2.97–3.1
Specific gravity
—
Black, may be brownish black
Streak
—
Semimetallic to dull
Luster
—
One direction, perfect k elongation, another fair ⊥ to first
Cleavage
—
C2/m
Space group
—
Straczekite
Structural group
—
Bkt · Approved
IMA
—
1963
Named in
—
Black; pale gray in reflected light
Typical colors
—
Al · Fe · V · O · H
Elements
—