how to facet
gemstone main cabochon creation
mineral data to quartz overview
Mineral Name: quartz
Gem Names: prase - chrysoprase
Chemistry: SiO2 (with Ni)
Class: silicate - cryptocrystalline
Crystal Sys: cryptocrystalline
Hardness: 7.0 Specific Gravity: 1.53 - 1.54
Fracture: uneven to conchodial Refractive Index: 1.53 - 1.54
Dispersion: none
Misc Prop: Prase is a leek green variety of quartz that contains the mineral chlorite. It looks a little like some varieties of amazonite but tends to be harder and more translucent. It is of little interest in the jewelry world.

Chrysoprase is a green chalcedony that gets its color from small amounts of nickel. It can be translucent to opaque with the apple-green translucent material the most desirable It may have colored veining running through it (tan to brown common).

It is considered the most expensive of the pure (non-patterned) chalcedony group and resembles high quality jade. The color can fade with heat so care must be taken when soldering around the stone.

Color: In gemstones, color, is often the key to naming or describing the particular variety. Hence look for this information below in the various descriptions. Color, opacity, and homogeneity often determine the placement of value on any given stone, and are all optical properties of the particular stone.
Specific Data:
high quality sample and more normal sample