Opal Identification

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Chemical composition of Opal:

Si0 2nH 20 – Hydrated Silica.

• Water content in Precious Opal 3-10%.

• Water content in Potch or Common Opal 2-20%

• Impurities are Oxides of:

Aluminium (~2.5%), Calcium (~1%), Sodium (~0.4%), Iron (~0.3%), Titanium and Magnesium (~0.1%) and in much smaller traces Zirconia, Manganese, Copper, Nickel and Cobalt.

Evaluation of Opal

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Opal is a complex stone to evaluate and this task falls mainly in the hands of experts with years of experience. There are eleven more facets to an Opal than the 4C's (Colour, Clarity, Cut, Carat) used to grade a Diamond. The factors outlined below provide a concise guide to the foremost influences on an Opals value:

Classification of Opal

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Australian Opal

‘Play of Colour’ is a unique visual phenomenon which sets precious Opal apart from all other gemstones. Also known as 'Fire'; An Opal may display one or more, and sometimes all of the spectral colours. These colours are seen within the grains of a pattern. As the stone is viewed from different directions, rotated and tilted, the colours of each grain may change or disappear.



Sue-White opals29 June 2013
Dear Rainbow Serpent,
Thank you for your email and membership.
It is great to know that you are out there promoting Australia's National gemstone & NSW emblem.
Keep up the good work, I love your concept.
Sue White - Orana Glitz & Glamour Extravaganza Inc Assn.

15 march 2013
Hi Peter,
Colourful characters are key,
your Facebook page and the photos look like there are some fantastic people!
We loved the look of Tarzan of Opalton.
Gemma Brady - Boundless productions.tv

Alexander fink.PhysicsPHD opal28 Nov 2012
I would like to welcome your information page on opal,
with detailed information about nearly everything their is to know in a general term.
Alexander Fink PhD - Dept. of Physics La Trobe University

5 August 2010
Hi from another opal lover.
Just wanted to say I love your site, a wealth of information.
I always send people to your page for opal info.
Kind Regards
Sean Tapner - Planet Opal

8 july 2010
Dear Rainbow Serpent,
Will be recommending your website as a primary reference to 15 Macquarie Uni media students who will be doing a PR project for us as part of their assessment soon.
Best wishes
Renata - Opalminded

Opalminded recommend opalsinformation6 June 2010
Dear Rainbow Serpent, 
Greetings from Opal Minded In Sydney.
We are all very impressed with your website – one of the best things that has happened to this Industry for a long time. 
We would love to share it with the visitors to our website. 
Would you mind If we post with us links to your website, 
also on our facebook and twitter. 
Best wishes
Renata, John, Nelly, Fabrice and Summer

Fri, Apr 16, 2010 
Good Morning,
I have just found your wonderful website.
I produce a monthly e-newsletter which is circulated to the Tourism businesses in Coober Pedy and neighbouring stations plus the Info Centres around SA & the NT.
I wondered if I could use some of your Opal info in my October Edition (Opal Month), mainly the parts in your “About Opal” section – names, spiritual info etc.
I would obviously reference it to your website noting the address so others could read your site. 
Sandra Harris
Tourism Officer - Coober Pedy Information Centre

5 April 2010
I am wanting to use your site in an assignment as it is a superb example
of a site to use for a primary teaching unit on gemstones.
Many thanks,