Tangeite

Formula: CaCu(OH)VO4

Origin of name: after locality Tange gorge, Fergana Valley, Kyrgystan

 

Crystal system: Orthorhombic

Crystal class: 222

Twinning:

Unit cell: a = 7.45, b = 9.26, c = 5.91

 

Colour: Green, dark green, yellowish green, yellow

Diaphaneity: Transparent to subtranslucent

Luster: Vitreous, pearly on cleavage

Habit: Granular, rare crystals are short prismatic, with acute terminations, typically in scaly rosettes and aggregates, botryoidal to spheroidal, fibrous, crusts

Hardness:  3.5

Specific gravity: 3.75

Cleavage: 2; {010} perfect, {001} good

Tenacity: Brittle

Streak: 

 

Synonyms/varieties:

 

Comments: originally considered to be calciovolborthite

 

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