Okenite with Gyrolite
Bombay, India
This specimen measures 12cm x 18cm
Okenite Ca10Si18O46.18H2O
Complex silicate containing both chain and sheet structures
Color and Luster: Colorless to white, also pale yellow or blue; pearly
Hardness: 4.5-5
Cleavage: One direction
Fracture: Flexible fibers
Crystals: Radial aggregates of filiform crystals
Gyrolite NaCa16(Si23Al)O60(OH5).15H2O
Sheet silicate, secondary mineral in basalt(diabase) cavities
Color and Luster: White, cream to gray, rarely green or brown; vitreous to pearly
Hardness: 3-4
Cleavage: Perfect in one direction
Fracture: Uneven
Crystals: Triclinic, lamellar radiating to spherical aggregates
Photo by Mary Sutherland
Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals
Descriptions taken from The Audubon Society Field Guide to North American Rocks and Minerals