Djurleite

Formula: Cu₃₁S₁₆

Origin of name:   For S. Djurle, chemist who first synthesised the compound later found in nature

Crystal system:   Monoclinic

Crystal class:   2/m

Twinning: Common on {110}

Unit cell: a = 26.897 Å, b = 15.745 Å, c = 13.565 Å, β = 90.13°

Colour:   Blackish lead-gray

Diaphaneity:  Opaque

Luster:   Metallic

Habit:   Crystals short prismatic or thick tabular; massive, compact

Hardness:   2.5 to 3

Specific gravity:   5.63

Cleavage:   None

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: Found with other secondary copper sulphides in enriched zones.