Yugawaralite

Formula: CaAl₂Si₆O₁₆.4H₂O

Origin of name: locality Yuawara Hot Springs, Kanagawa Prefecture, Japan

Crystal system: Monoclinic

Crystal class: m

Twinning: on {-111} polysynthetic; on {-101} contact

Unit cell: a = 6.728 Å, b = 14.01 Å, c = 10.06 Å, b = 111.2°

Colour: Colourless to white

Diaphaneity: Transparent to translucent

Luster: Vitreous

Habit: Crystals flat, mostly small, to 20 mm

Hardness: 4.5

Specific gravity: 2.23

Cleavage: [010] indistinct

Tenacity: Brittle

Streak: White

Synonyms/varieties:

Comments: member of the zeolite group