Erionite

Formula:   (K₂,Ca,Na₂)₂Al₄Si₁₄O₃₆ ^. 15H₂O

Origin of name:   From Greek for wool

Crystal system:   Hexagonal

Crystal class:   6/m 2/m 2/m

Twinning:

Unit cell: a = 13.24 Ǻ, c = 15.1 Ǻ

Colour:  White

Diaphaneity:

Luster:   Vitreous to silky

Habit:   Crystals prismatic, minute, in radiating groups; finely fibrous and wool-like

Hardness:   3.5 to 4

Specific gravity:   2.02

Cleavage:   None

Tenacity: 

Streak:   White

Synonyms/varieties:

Comments: