CIBJO releases Gemmological Special Report: considers process of separating measurable facts from opinion; See Gemological Articles below.
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 Post subject: Synthetic opal?
PostPosted: Thu Jun 28, 2012 10:11 am 
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I´m sure this subject been up before but I can´t find it with the searchfunction...

How can I recognize or test an opal to be sure it isn´t synthetic?
And I don´t mean a doublet or a triplet, and I´m not talking about fireopals or mexican or pink or blue or white opals. I mean those with all the lovely colors in it, such as welo or Australian (black, grey white?) ones.

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 Post subject: Re: Synthetic opal?
PostPosted: Thu Jun 28, 2012 11:16 am 
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Magnification, I think? I was taught that the play-of-color patches look different in synthetics under high magnification... they'll have a mosaic or hexagonal sort of appearance, and look long and columnar from the side of the cabochon.

There are some photos on geminterest of the structures: http://www.geminterest.com/inclist.php? ... th%E9tique

I don't know if this is true of all synthetic phenomenal opal. :?: Someone please correct me if I'm wrong or omitted something.


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 Post subject: Re: Synthetic opal?
PostPosted: Thu Jun 28, 2012 1:58 pm 
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Yes, magnification and knowing what is natural and what isn't.

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 Post subject: Re: Synthetic opal?
PostPosted: Thu Jun 28, 2012 2:37 pm 
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Lennie wrote:
How can I recognize or test an opal to be sure it isn´t synthetic?

The answer is far more complex than it might appear. The problem is there are many kinds of synthetic opal and opal imitations/simulants so there's no single or simple answer.

The biggest synthetic opal players are Gilson and Inamori (Kyocera) but Russian synthetics and others from Asia are well dispersed into the market. Gilsons are fairly easy to ID due to the "snakeskin" appearance of the top of columnar grains in the opal. Viewed from the side the columns are quite apparent. But I've seen columnar arrangements in natural Brazilian opal and the Welo material is presenting a huge array of honeycomb and other new and unusual patterns.

There really isn't a lot of reliable information on this topic, in my opinion. As a long-time opal fancier I've made a point of looking for it. I think the issue has largely been ignored by the main body of U.S. gemology because opal doesn't account for a big dollar share of the overall gem market. Besides, until recently, opal market "action" has been pretty much confined to Australia.

You might do a search for Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) literature on the subject because historically that country has had a vested interest in the integrity of opal sales. It was CSIRO scientists who first discovered the cause of the play of color in precious opals.

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 Post subject: Re: Synthetic opal?
PostPosted: Thu Jun 28, 2012 3:50 pm 
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Thanks for the insight... opals really are a different beast from everything else, it seems


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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 2:00 am 
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Thank you all, and especially ROM. Interesting read.
I didn't like opals before but then I bought some and I can't take my eyes of of them! I really love the play of color in them! Now I just want more and more of them, but it's a matter of cost... My family has to eat, too... :wink:

I don't like treated or synthetic gems. If I hold a gemstone in my hand and KNOWS it is all natural, it feels in a whole different way than with a treated gem. The nature formed this in it's own way, that feels good! =D>

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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 2:30 am 
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Hi Lennie,

The topic of synthetic opal is interesting. There are some who say that most of the "synthetic" opal on the market is really an imitation, not a true synthetic, because it lacks any water in its makeup.

Here are some articles I had archived: http://www.chileangems.com/Opal_Description.htm

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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 5:44 am 
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Synthetic, lab-grown, man-made... That was a funny discussion ROM! :mrgreen: I wonder what the result was???

To clarify my question:
How can I see, test, exam or anything else, if the opal in my hand is natural or something else? :wink:

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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 7:12 am 
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Identifying some synthetic colored stones can be very tricky and much more difficult comparing to Sapphire/Rubies/Emerald Synthetics which most of the time an expert gemologist can Identify them by magnification even with 10X loupe

Opal, Citrine, Amethyst, Onix,... are some example which one should be careful and identifying them with magnification is not simple

as for opal there many type of imitations and synthetics and there are many stuff to be said about identifying them and one needs to study and get experience to identify them.

anyway some of synthetic and imitation opals can be identified by magnification, The Lizard Skin, Chicken wire effect in and relationship of their patterns with the columnar structure would help to ID them but some synthetics can get tricky like Severny Opal (synthetic of Australian Noble Opal). i myself would not judge them by just magnification!

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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 4:48 pm 
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roshanravan wrote:
Identifying some synthetic colored stones can be very tricky and much more difficult comparing to Sapphire/Rubies/Emerald Synthetics which most of the time an expert gemologist can Identify them by magnification even with 10X loupe

Opal, Citrine, Amethyst, Onix,... are some example which one should be careful and identifying them with magnification is not simple

as for opal there many type of imitations and synthetics and there are many stuff to be said about identifying them and one needs to study and get experience to identify them.

anyway some of synthetic and imitation opals can be identified by magnification, The Lizard Skin, Chicken wire effect in and relationship of their patterns with the columnar structure would help to ID them but some synthetics can get tricky like Severny Opal (synthetic of Australian Noble Opal). i myself would not judge them by just magnification!



I knew that amethyst, citrine and onyx was tricky but I didn't know about opals...
I have SO much to learn and probably way to little time... #-o

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 Post subject: Re: Synthetic opal?
PostPosted: Fri Jun 29, 2012 4:52 pm 
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Quote:
I have SO much to learn and probably way to little time...


:(

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 Post subject: Re: Synthetic opal?
PostPosted: Sat Jun 30, 2012 4:00 am 
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Lennie wrote:
I knew that amethyst, citrine and onyx was tricky but I didn't know about opals...
I have SO much to learn and probably way to little time... #-o

the more i learn and study the more i realize that i know nothing and every day it is a new challenge specially with treatments and synthetics.
synthetic black Severny Opal is an example which has quite similar characteristics of noble balck opal. also grading Opal is very interesting.

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 Post subject: Re: Synthetic opal?
PostPosted: Sat Jun 30, 2012 5:40 am 
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Jason wrote:
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I have SO much to learn and probably way to little time...


:(



It´s not THAT bad yet, Jason! But we´ll see in a couple of months, there are a new Swedish method that I MIGHT be able to try soon...
For all of you who wonders what the heck I´m talking of - Jason knows I´m fighting against cancer...

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 Post subject: Re: Synthetic opal?
PostPosted: Sat Jun 30, 2012 9:47 pm 
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There are the types that have synthetic opal growth, but are suspended in a polymer base. These are easier ID's than the real synthetics.

In our lab, infrared works for us quite in identifying all of them. But I will say that there are some very good ones out there.

Bear Williams


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 Post subject: Re: Synthetic opal?
PostPosted: Mon Jul 02, 2012 10:56 am 
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Thank you all.
Now I know more, or maybe not... #-o :wink:

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