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New Opal (Homogeneously Crystalized)
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Author:  goldberg [ Tue Mar 14, 2017 4:46 pm ]
Post subject:  New Opal (Homogeneously Crystalized)

Just for your information:

I’m very happy to see that now it is possible to prepare opals without columnar patterns.

These opals with homogeneously crystallized silica particles in a polymer matrix (= HoC-Si-Pol) don’t show a columnar pattern typical for opals grown by sedimentation.
With big polygonal crystallites of 2-3 mm these multicolored opal can be produced in big blocks and different body colors.

Image

For more information please visit:

http://www.synthetic-opals.com

By use of a modified technology now fine crystalline „Aurora Opals“ are available:

http://www.aurora-opals.com

Image

Author:  Osman khattak [ Mon Mar 20, 2017 2:24 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

:shock: :shock: :shock:

Author:  Barbra Voltaire [ Mon Mar 20, 2017 7:25 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

Quote:
homogeneously crystallized silica particles in a polymer matrix


By definition, a synthetic gem is a man-made material with essentially the same chemical composition, crystal structure and optical and physical properties as the natural gem material.

I don't think your stone can be called synthetic opal.

Author:  Stephen Challener [ Mon Mar 20, 2017 8:45 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

I think almost all man-made opal is polymer impregnated. It is one of those odd edge-cases, since natural opal can be polymer impregnated as well in post, and it would still be opal. Opal beads can also crystallize after formation so that isn't necessarily a disqualifying factor either.

Author:  Barbra Voltaire [ Mon Mar 20, 2017 10:56 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

Fair enough.....

Author:  Stephen Challener [ Mon Mar 20, 2017 11:55 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

I agree though that it is a weird edge case and has some definite differences to natural material. Hopefully that will make for easier identification, given how different this looks from traditional synthetic material.

Author:  Bill Hanneman [ Tue Mar 21, 2017 1:15 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

Just call it artificial. :)
The word synthetic has no meaning relative to value.

Author:  Stephen Challener [ Tue Mar 21, 2017 4:25 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

Bill Hanneman wrote:
Just call it artificial. :)
The word synthetic has no meaning relative to value.

That's not true when it comes to opal. Metal foil in glass or resin could look superficially similar in a photo but in person the resemblance is slight.

Author:  Barbra Voltaire [ Wed Mar 22, 2017 5:50 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

I would tend to call these opals an artificial product as well.

Like CZ.
Yes, Baddeleyite (ZrO2 occurs naturally, but it never contains the dopants (lower-valence oxides like Ca
O, MgO, or Y2O3 which make it crystallize in the cubic system.

Author:  Tom Herman [ Wed Mar 22, 2017 11:44 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

I would call it a simulant, as it is not an opal.
A synthetic, or lab created opal would largely have the same characteristics as natural opal, which this clearly does NOT, as it is roughly 80% plastic, vs. 20% SiO2, and its specific gravity is horrendously off (much lighter than real opal) ...

Author:  goldberg [ Thu Mar 23, 2017 12:25 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

Is it only important how to call the material?

Nobody wants to know what „homogeneously crystallized“ means?

Here's an example, which also shows that a material with play-of-color does not necessarily have to be solid:

https://www.youtube.com/watch?v=rvNmH96dqAw

Author:  Barbra Voltaire [ Thu Mar 23, 2017 4:40 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

This is a professional gemological forum, Goldberg.
Yes, as gemologists, mineralogists and chemists we DO want to know what "homogeneously crystallized“ is intended to mean in regards to opal and whether or not it is just a deliberately obfuscating description.

Pretty video on crystalline suspension of colloidal silica particles but what does that have to do with calling a predominately plastic product a synthetic opal?

Author:  Stephen Challener [ Thu Mar 23, 2017 6:59 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

When they say "colloidal crystal" on the vodeo I believe they are referring to the concept of a photonic crystal (ie an orderly arrangement of particles that diffracts light the way a crystal diffracts xrays). It would be weord to use the term "homogenously crystallized" to refer to that phenomenon.
I could see synthetic vs simulant going either way, but we already call other resin-infused products synthetics, and since it is used as a binder for silica particles arranged in the same way as in a natural opal I don't mind it much. One way or another it is quite different from lesser imitations. Seems like the end product might be like taking one of those Ethiopian chalk opals and soaking it with resin.
Fortunately that should make distinguishing them relatively easy, which is always a big plus.

Author:  AlBalmer [ Thu Mar 23, 2017 7:58 pm ]
Post subject:  Re: New Opal (Homogeneously Crystalized)

"Homogeneously crystallized“ just means that the nucleation starts within the mix, rather than from the surface. I think this is just another example of using big words to impress potential customers. As for the simulant/synthetic question, I'll leave that to you gemologists :-) It's obviously not natural opal.

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