Composition: Al2(F,OH)2SiO4
crystal System:  Orthorombic
Habit: Prismatic, with dome and / or pyramidal terminations
Refractive Index: 1.61-1.62 (colourless, brown,yellow)
Double Refraction and Optic Sign: 0.01 (colourless, brown, yellow) negative 1.63-1.64(red,pink,orange)
Dispersion: Low (0.014)
Specific Gravity: 3.53-3.56
Hardness:  8.0
Cleavage: Prfect,Basal
Fracture: Subconcohoidal to uneven
Lustre:  Vitreous
Pleochroism: Distinct to strong depending on depth of the body colour
Luminescence: Weak, red, pink, light brown and yellow stones may fluoresce orange-yellow in long wave ultra violet
Absorption Spectrum: In red and pink there is a band in the red at 683.8nm
Inclusions: Cavities containing two immiscible liquids, and long tube like cavities
Occurrence:  Africa and Asia, with Brazil as most the most important source.

Topaz


Topaz can be the amber gold colour of fine cognac or the bluish pink-orange of a peach and all the warm brown's, gold's, and orange's in between, some rare and very exceptional stones are pale pink to a sherry red. All of these colours are known as precious Topaz. Blue Topaz is an affordable gem, has an enhanced colour, Topaz with a natural blue colour is very rare. The Egyptians said that Topaz was coloured by the golden glow of their mighty Sun god "Ra". This made Topaz a very powerful amulet that protected the faithful against harm. The Romans associated Topaz with Jupiter, who also is the god of the Sun.
Wear Topaz only if you wish to be clear sighted, as legend has it Topaz dispels all enchantment and helps to improve eyesight as well. The ancient Greeks believed that Topaz had the power to increase strength and make it's wearer invincible in times of emergency. Topaz was also said to change colour in the presence of poisoned food or drink. It's mystical curative powers waxed and warned with the phases of the moon, and was said to cure insomnia, asthma and haemorrhages.

John Cadby Jewellers
 Goldsmith, Silversmith,
Diamond Merchants, Appraiser & Engraver.
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3, White Hart Yard, Trowbridge, Wiltshire.  BA14 8BY
Tel: 01225 776322  E-Mail: John@Cadby.co.uk

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