Color: Green, to yellow/green, green/blue…
Moh’s Hardness: 7-7.5
Refractive Index: 1.616-1.652
Critical Angle: 38.23°
Specific Gravity: 3.02-3.26
Fracture: Uneven, small conchoidal
Heat Sensitivity: Not usually a problem
Dichroic: Strong (many color variations)
Birefringence (double refraction): Medium (.014-.024)
Crystal structure: Hexagonal
Color: Chrome Green
Chrome Tourmaline is mined in Tanzania (Africa)… Supply is sporadic, so is the pricing. But quality material is always in short supply and demands top dollar. It is seldom very large and generally when it is large it is too dark and not clean.
Treatments: Sometimes heated to lighten darker colors. Not much other treatment…
What I prefer to polishing with: Alumina oxide with a tin lap (scored).
Jeff’s Comments: Cuts and polishes like any other Tourmaline, usually no problems… Orientation is important, go for the best color. The “c” axis on this material is often dark and must be orientated correctly.
Design Notes: About any Tourmaline design will work well, although I generally prefer a shallow checkerboard on darker rough. Use a design like my Smith Bar for dark axis material…
Design Links: Signature #4 – This is good for about any rough
Easy Emerald – This is a classic and works well on poor “c” axis colored stones
Smith Bar – This is a classic and works well on poor “c” axis colored stones