Bukovite

Formula:  Tl₂(Cu,Fe)₄Se₄

Origin of name:  From locality, Bukov, Czech Republic

Crystal system: Tetragonal

Crystal class: 4/m 2/m 2/m

Twinning:

Unit cell: a = 3.976 Å, c = 13.7 Å

Colour:  Grayish brown

Diaphaneity:  Opaque

Luster:  Metallic

Habit:  Massive

Hardness:  2

Specific gravity:  7.36

Cleavage:  2; {001} good, {100} imperfect

Tenacity:

Streak:

Synonyms/varieties:

Comments: Found in calcite veins of hydrothermal origin, in metamorphic rocks