Guanajuatite

Formula:  Bi₂Se₃

Origin of name:   Locality; Guanajuato, Mexico

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell:

Colour:  Lead gray with bluish tint

Diaphaneity:  Opaque

Luster:  Metallic

Habit:  Crystals acicular, striated, in masses; massive, fine-granular or fibrous

Hardness:  2.5 to 3.5

Specific gravity:  6.25 to 6.96

Cleavage:  2; {010} distinct, {001} indistinct

Tenacity:

Streak:  Shiny grey

Synonyms/varieties:

Comments:  Dimorphous with paraguanajuatite