VS
Name
—
Bi₂Te₂S
Formula
—
Mineral Species
Entry type
—
Sulfides
Chemical class
—
Hexagonal
Crystal system
—
1.5–2
Mohs hardness
—
7.3
Specific gravity
—
Pale steel-gray
Streak
—
Metallic, splendent on fresh surfaces. Anisotropism: Weak. R1 –R2: (400) 51.9–56.8, (420) 52.0–56.9, (440) 52.0–57.0
Luster
—
Perfect on {0001}
Cleavage
—
R-3
Space group
—
Tetradymite
Structural group
—
Ttd · Grandfathered
IMA
—
1831
Named in
—
Pale steel-gray, tarnishes dull or iridescent; in polished section, white
Typical colors
—
Bi · Te · S
Elements
—