I’m curious if you can help me with this stone. Video link below.
I am not sure it is real Opal or not.
I’ve had opinions both ways but regardless of the opinions, I’m looking for data that supports any opinions.
Thank you!
Hi,
could it be natural ethiopian welo white pinpoint/ pinfire honeycomb/ harlequin opal…
julie
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I’ve cut well over 100 opals and I can’t tell from your video. The faint white “spiderwebbing” seems just a little odd, but maybe that’s an artifact of the lighting or the setting. If the pattern, colors, and brightness are uniform across the entire face, that could suggest that it is manufactured, but it would not be definitive.
If you could get to the back of it, you could test its hardness. Opal is in the 5.5 - 6.5 range…Rob
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I lost my post inadvertently twice. Take the stone to a GIA certified gemologist. So far as getting to the back of the stone and scratch testing it is concerned, regular glass has a Moh’s hardness overlapping opal… 5.5 to 7 depending on it’s composition and method of manufacture. If you are going to do it yourself scratch test it using a Moh’s hardness kit, be sure that the scratch will not be visible from the front and start with a hardness of five…
Just for FYI: iPhones have Gorilla glass…it’s gone thru a lot of iterations by Corning since it’s first creation. Gorilla glass 6 has a Mohs hardness of 7 although some references put it at 9… Corning found it so tough and hard to work, requiring boron nitride or diamond coated tools that it was going to give up on it before the late Steve Jobs, the founder of Apple came to Corning for a very tough, scratch resistant glass. What I found interesting about it is that’s toughness comes about from internal compression…like reinforced concrete… potassium ions are exchanged for sodium ones in a high temperature chemical bath… potassium ions have a large ionic radius than sodium ones, giving the glass internal compression like reinforced concrete…Gorilla glass is even more shock and crack resistant than the best tempered glass… which is why iPhone don’t break when you drop them, even on the sidewalk!.. I found that interesting… off the subject but interesting!!
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Thanks for all your input. I have found out from speaking to an Australian opal dealer that it is real old stock out of Coober Pedy.
Much appreciated!
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great! a truly valuable stone…congrants, but still would get a professional opinion for a GIA gemologist, especially for something that valuable
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Thank you, I will definitely look into that.
hope you get a pleasant surprize…
The coloration looks good and consistent for a white opal from Australia. The color play is distributed randomly versus something more uniform. The webbing is natural but undesirable since it breaks up the view of the face of the opal and detracts from the color play. Can you see the back of the stone? Looking for small pieces of potch or whatnot helps with identification, but white opal is typically cut without potch compared to boulder and black opal.
have you found the answer to your question? If you do, please post it… I think that everyone is curious to know… thanks, steve
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I haven’t taken it and paid for GIA certification, but I’ve gotten advice from a professional opal dealer that it is real. I responded above as well. Cheers!
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old stuff out of Coober Pedy…did they put a value on it… it’s a good stone, Coober Pedy is mined out so far as I know now… congratulations.!
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It’s real but…The spider webbing looks like it may be the fine cracks of a crazed opal to me. it happens when an opal is over exposed to sunlight, heat, etc. From GIA…Opal Quality Factors | Types of Opal | GIA.
“If an opal loses moisture, it can lead to crazing: a fine network of cracks that resembles a spider’s web. The moisture loss can be caused by heat or excessive dryness, or by exposure to bright light or direct sunlight.”
I wouldn’t buy it.
Jo
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Well it’s not for sale! 
It’s definitely an old piece, and probably won’t be used in a piece for sale to the public. This is one piece in a group of pieces.
I don’t mind the crazing but I know it reduces the value in the general market.
Our father always kept his opal rough and finished stones in a vial of glycerin…Rob
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I’ll look into that. Thank you
don’t let opals or pearls dry out…more important in the desert than humid climates, but the air will be dry in the house with winter heating…see below… IGA recommends storing them in a moist cotton. They say not to ue oil or glycerin because of the mess cleaning them off.
Opal and Pearl Care Guide - International Gem Society
[image]
International Gem Society
https://www.gemsociety.org › … › Gemology
](Opal and Pearl Care Guide - International Gem Society)
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