Spangolite

Formula: Cu₆Al(SO₄)(OH)₁₂Cl.3H₂O

Origin of name: for N. Spang, American collector

Crystal system: hexagonal

Crystal class: 3m

Twinning: rare on {0001}

Unit cell: a = 8.25 Å, c = 14.34 Å

Colour: dark green, emerald-green, bluish green

Diaphaneity: 

Luster: vitreous

Habit: crystals short prismatic or tabular, holohedral or hemimorphic, hexagonal in aspect, striated

Hardness: about 3

Specific gravity: 3.14

Cleavage: 2; {0001} perfect, {10-11} distinct

Tenacity: conchoidal, brittle

Streak: pale green

Synonyms/varieties:

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