how to facet
gemstone main cabochon creation
mineral data
Mineral Name: prehnite
Gem Names: prehnite
Chemistry: Ca2Al2Si3O10 (OH)2
Class: silicate - phyllosilicates
Crystal Sys: orthorhombic
Hardness: 6 - 6.5 Specific Gravity: 2.82 - 2.94
Fracture: uneven Refractive Index: 1.611 - 1.669
Dispersion: none
Misc Prop: Prehnite can be cut into either cabochons or faceted stones, but faceted stones are very rare. The colors range from yellow-green to a brown-yellow. Although the hardness is not bad, it does suffer from good cleavage which can make setting the stone a bit more difficult. catseye prehnite is also know.

It is rarely seen in jewelry and is more of a collectors stone in both the cabochon and especially the faceted stones. It was named for its discoverer, Hendrik von Prehn, a Dutch colonel.

Below is an examole of a simple prehnie cabochon.

Specific Images:
a small prehnite cabochon