Arcanite

Formula:  K₂SO₄

Origin of name:  Latin alchemical name for compound

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell: a = 5.76 Å, b = 10.05 Å, c = 7.46 Å

Colour:  Colourless, yellowish

Diaphaneity: Transparent

Luster:  Vitreous

Habit:  As thin plates, pseudo-hexagonal from cyclic twinning

Hardness:  2

Specific gravity:  2.66

Cleavage: 1; {010} and {001} good

Tenacity:

Streak: White

Synonyms/varieties: ammonium arcanite, potassium sulphate, taylorite

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