Aluminite

Formula:  Al₂(SO₄)(OH)₄^.7H₂O

Origin of name:  From Latin alumen = alum

Crystal system:  Monoclinic, pseudo-orthorhombic

Crystal class: 2/m 

Twinning:

Unit cell: a = 7.44 Å, b = 15.583 Å, c = 11.7 Å, b = 110.18°

Colour:  White to grayish

Diaphaneity: Opaque

Luster:  Dull, earthy

Habit:  Nodular masses of minute fibres; spherulitic; veinlets

Hardness:  1 to 2

Specific gravity:  1.66 to 1.82

Cleavage:  None

Tenacity:

Streak: White

Synonyms/varieties:

Comments: