Ekanite (calcium sodium potassium thorium silicate)
Color: Green to light brown
Moh’s hardness: 6-6.5
Refractive index: 1.57
Critical angle: 39.5°
Specific gravity: 3.3
Heat sensitivity: Low
Birefringence (double refraction): Weak (.001)
Crystal structure: Tetragonal
Polishing: Alumina on tin/lead or tin.
Comments: Ekanite is radioactive. Dispose of cutting waste immediately and keep all surfaces clean. Try not to breathe close to the cutting surface and store stones away from living and working areas. Better yet, cut something safer.