Wilkmanite

Formula: Ni₃Se₄

Origin of name: for Wanold Wrydon Wilkman (1872-?), Finnish geologist

Crystal system: Monoclinic

Crystal class: 2/m

Twinning:

Unit cell: a = 6.22, b = 3.63, c = 10.52, β = 90.53°

Colour: Grayish yellow, pale greenish yellow in reflected light

Diaphaneity: Opaque

Luster: Metallic

Habit: Massive

Hardness: about 2.5

Specific gravity: 6.96 (calculated)

Cleavage: 1; {001} good

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: dimorphous with trüstedtite