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
Treatments: Heat is sometimes used to lighten rough and get rid of undesirable color… Radiation is used on cut stones to improve color, but it is not commonly used on rough (usually stones are cut first and then irradiate).
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. Be careful about over saturation, stones can be dark sometimes.
Design Notes: About any Tourmaline design will work well, although I generally prefer a shallow checkerboard on darker rough. Pick a design with the correct depth for the rough you have. Light rough deep design, dark rough shallower design.
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