Moh’s hardness: 2
Refractive index: 1.52
Critical angle: 41°
Specific gravity: 2.3-2.33
Cleavage: Perfect in 1 direction and strong in 2 directions.
Fracture: Extremely splintery
Heat sensitivity: High
Birefringence (double refraction): Weak (.009)
Crystal structure: Monoclinic
Cutting: Cleavage is so strong that it will split apart during sawing and performing. Extra-fine laps should be used at all cutting stages.
Polishing: Wax lap with alumina at slow speed.
Comments: Only use adhesives for dopping. Selenite is one of the most challenging of all stones to facet. If you are a glutton for punishment, this one’s for you.