Silinaite

Formula: NaLiSi₂O₅.2H₂O

Origin of name: from elements in composition

Crystal system: monoclinic

Crystal class: 2/m

Twinning:

Unit cell: 

Colour: white to colourless

Diaphaneity: opaque to translucent

Luster: vitreous to earthy

Habit: clear tabular crystals to 2 mm, fibrous clusters, chalky to earthy or powdery patches in cavities

Hardness: 4.5

Specific gravity: 2.24

Cleavage: 3; {001} perfect, {010} good, {110} distinct

Tenacity: 

Streak: white

Synonyms/varieties:

Comments: slowly soluble in concentrated HCl, HNO₃ or H₂SO₄  leaving gelatinous residue