White or colourless stones
White or colourless stones
Hardness. Specific Gravity.
Beryl 7-3/4 2.709-2.81
Corundum 9 3.90-4.16
Diamond 10 3.502-3.564
Jade 7 3.300-3.381
Opal 5-1/2-6-1/2 2.160-2.283
Phenakite 7-3/4 2.965
Quartz 7 2.670
Rock-crystal 7 2.521-2.795
Sapphire 9 4.049-4.060
Spinel 8 3.614-3.654
Topaz 8 3.500-3.520
Tourmaline 7-1/4 3.029
Zircon 7-1/2 4.700-4.880
