Little Gems
http://tjlittlegems.com
Gem Rough
listings Cut stones listing
Scapolite
Sunstone
Specials
News Letter (click to send a subscription request email.)
Sapphires
|
|
Australian Sapphires Nigerian Sapphires - Nice blocky pieces, slightly water warn. African Rubies - Nice medium saturated colour. |
Cutting Information for Sapphire and all Corundum (all colours).*
Colour: All colours including clear/colourless.
Moh’s Hardness: 9.0
Refractive Index: 1.762-1.778
Critical Angle: 37.62°
Specific Gravity: 3.95-4.03
Fracture: Splintery/Irregular, Conchoidal
Cleavage: None
Dispersion: Medium (.014)
Heat Sensitivity: Generally not heat sensitive.
Dichroism: Occasionally present in certain colours.
Birefringence (double refraction): Low (0.008-0.009)
Crystal Structure: Trigonal, massive