Barrerite

Formula:  (Na,K,Ca)₂Al₂Si₇O₁₈ ^. 7H₂O

Origin of name:  For Richard Maling Barrer (1910- ), New Zealand-born British teacher and chemist, known for his study of zeolites

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell:

Colour:  White, pink

Diaphaneity: Transparent to translucent

Luster:  Vitreous

Habit:  Laminar crystals to 5mm

Hardness:  Unknown

Specific gravity:  2.13

Cleavage:  1; {010} perfect

Tenacity:

Streak:

Synonyms/varieties:

Comments: Zeolite group. Found on the walls of large fractures in deeply weathered andesitic and rhyolitic lavas associated with heulandite