Tomichite

Formula: (V,Fe)₄Ti₃AsO₁₃(OH)

Origin of name: for Stephan A. Tomich (1914- ), Australian consulting geologist who discovered the mineral

Crystal system: Monoclinic

Crystal class: 2/m

Twinning:

Unit cell: a = 7.119, b = 14.176, c = 4.992, β = 105.05°

Colour: Black

Diaphaneity: Opaque

Luster: Resinous

Habit: crystals euhedral, tabular, to 3 mm

Hardness: 6

Specific gravity: 4.16

Cleavage: None

Tenacity: Conchoidal fracture

Streak: Black

Synonyms/varieties:

Comments:  Found in a specimen from a hydrothermal gold deposit.