Chemical composition -- A hydrated calcium aluminum silicate with iron.
Color -- Various shades of green, yellow, gray, or white.
Optics -- R.I 1.61-1.66.
Durability -- Hardness 6-6.5. Brittle.
Crystal structure -- Orthorhombic.
Specific Gravity -- 2.8-3.0.
Sources -- Many locations, including the U.S.A., China, Canada, Australia, Scotland, and France.
Prehnite is often cut as cabochons or carvings. It occasionally shows a cat's-eye effect. Some yellow to green translucent material from Australia has been faceted.