Composition: SiO2H2O  a hydrated silica containing upto 10% waer in chemical composition
crystal System:  non crystalline
Refractive Index: 1.45
Specific Gravity: 2.1
Hardness:  6.0
Lustre:  Vitreous
Occurrence:  Mainly New Soth Wales and Queensland in Australia, Brazil, Mexico (Fire Opal), USA

Opal

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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