Little Gems
http://tjlittlegems.com
Gem Rough
listings Cut stones listing
Scapolite
Sunstone
Specials
News Letter (click to send a subscription request email.)
Topaz
|
|
Imperial
Light peachy coloured topaz. Pale blue Lighter than sky blue, but still blue. Sky blue A real nice blue.
|
Cutting Information for Topaz (all colours).*
Colour: Clear/colourless to blues
and rarely reds and "champagne" colours.
Moh’s Hardness: 8.0
Refractive Index: 1.630-1.638
Critical Angle: 37.50°
Specific Gravity: 3.4-3.6
Fracture: Irregular, Sub-Conchoidal
Cleavage: Perfect (7° of C-axis)
Dispersion: Moderate (0.014)
Heat Sensitivity: Generally not heat sensitive.
Dichroism: Occasionally present in certain colours.
Birefringence (double refraction): Weak (0.01)
Crystal Structure: Orthorhombic