Items marked sold may still be available there. Happy Shopping!
Rhodochrosite (manganese carbonate)
Color: Rosy-red to pink.
Moh’s hardness: 3.3-3.7
Refractive index: 1.6-1.82
Critical angle: 38.5° for low RI and 33.5° for high RI.
Specific gravity: 3.3-3.7
Cleavage: Perfect in 3 directions.
Fracture: Uneven, conchoidal, brittle
Heat sensitivity: Moderate
Birefringence (double refraction): Very strong (.22)
Crystal structure: hexagonal, trigonal
Cutting: Orient the stone to avoid cleavage planes and use a fine lap for cutting.
Polishing: Alumina on tin/lead or wax lap, or chrome oxide Ultralap.