Chlorothionite

Formula:  K₂Cu(SO₄)Cl₂

Origin of name:  From Greek for chloro = green theion = sulfur

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell: a = 7.73, b = 6.078, c = 16.292

Colour:  Bright blue

Diaphaneity:

Luster:

Habit:  Crystalline incrustations

Hardness:  2.5

Specific gravity:  2.69

Cleavage:  3; {100}, {010}, and {001} good

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Soluble in water