VS
Name
—
Cu₇TlSe₄
Formula
—
Mineral Species
Entry type
—
Sulfides
Chemical class
—
Tetragonal
Crystal system
—
2.5–3
Mohs hardness
—
6.9
Specific gravity
—
—
Streak
—
Metallic. Anisotropism: Weak but distinct, in brownish tones. R1 –R2: (400) 33.6–35.9, (420) 33.3–35.8
Luster
—
Two at right angles, fairly well developed
Cleavage
—
I4/m
Space group
—
—
Structural group
—
Crk · Grandfathered
IMA
—
1867
Named in
—
Lead-gray
Typical colors
—
Cu · Tl · Se
Elements
—