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[Jw]

What is your opinion on bello opal or synthetic 

[Stonemon]

Hello @Jw, I don't dabble in opals but welcome to the forum!

[Jw]

Thanks what do you dabble in?

[ileney]

Do you mean Bello opal like sold on Sanwa opals? At a quick glance, most seem obviously NOT earth mined as they are in improbable patterns and colors that run all the way through, but they are still pretty. But that’s just my opinion.

[R.U. Sirius]

Depends what you want to do with opals. Jewelry, or larger art pieces, decorative items, mass produced or hand-made one-of-a-kind...? low-cost or high-end market?

[vitzitziltecpatl]

Welcome.

I think I agree with Ileney. Pretty - but most people would recognize it as synthetic. It "Siriusly" does depend on the intended use.

[Jw]

I was thinking of carving stuff from it and if I sold anything I would tell them it was lab grown and not mined

[vitzitziltecpatl]

I'm not a carver, but that material should work well for carving pieces viewed from the face only.

Some synthetics look really "fake" from the sides.

[VegasJames]

There is some question if it is really opal. Opal contains around 3-21% water. What is being sold as lab made opal from what I have heard does not contain water. This makes sense as a lot of the so-called lab opal is used by glass blowers in their work. The water in opal would rapidly turn to vapor and blast apart the opal. Therefore, I would not even call this stuff opal as it does not contain water.

[Jw]

And  a lot of them contain resin as well as silica I wasn’t really concerned with how close it was to real opal just that it looks cool and is cheaper so good for broke people

[VegasJames]

And  a lot of them contain resin as well as silica I wasn’t really concerned with how close it was to real opal just that it looks cool and is cheaper so good for broke people

Not that hard to make opal. Takes about a year to complete though. I have done jelly opal and common opal Still trying to make precious opal, but some of my more recent experiments look pretty promising.

One of the things I have not liked about most of the synthetic "opal" is that most of looks like complete crap.

And yes, some is impregnated with resin because the way they are making and drying it leads to pretty weak, unstable material. If they took the time to make true opal as nature does then the material would be a lot more stable , but you still would not be able to subject it to heat the way the stuff they are erroneously calling opal can be.

[Jw]

How do you make it ?

[VegasJames]

How do you make it ?

Won't get in to details. If someone really wants to know then the research is out there. I figured it out with just some experimenting, but there is research out there on the use of TEOS as a silica source.  And there are various factors that have to be watched such as temperature, which plays a big role in the final colors, as well as nucleators, allowance of sedimentation, etc.

My experiments are more focused on mimicking nature's production like Len Cram from Australia did.  https://www.sunriseopals.com/pages/len-cram-an-opal-icon#:~:text=In%20his%20jars%2C%20the%20first,over%20subsequent%20months%20and%20years.  I got in to experimenting with the idea of making opal before I heard of Len Cram. Reading his story though re-peaked my interest in the project and based on what I could find on his research gave me new ideas to experiment with based on what materials I know he is using and associated minerals naturally found with opal as well as opal formation such as volcanic and sedimentary. It is much like a jigsaw puzzle, and you have to find all the pieces of the puzzle and put them all together.

I have quite a few years of research in to this and many files of opal formation notes and studies.

The first opal I made used kitty litter (bentonite clay). And yes, it was clean. Little dark floaty things in the mix does not make good nucleators. I have experimented with various materials, even have one going right now using Pepto Bismol.

What I will say about the process is that it does take a lot of patience. About 6 months to finish hardening in to a gel, then at least another 6 months of very gradual drying to stabilize the material.  Not like rubies/sapphire, diamonds, etc, that can all be made in a short time.

[R.U. Sirius]

For anyone considering experimentation with TEOS or other similar precursors: only do so in a proper laboratory setting, and with proper level of understanding of chemical safety risks and mitigation strategies. If you think breathing in silica dust is bad (it is), consider breathing in vapors of a precursor chemical that reacts with moisture to produce silica right there, in your lungs or eyes. Add to this the risk of fire or explosion.

Once health and safety have been addressed, this becomes a really interesting topic, as @VegasJames explained. The commercially available materials mentioned in this thread originally are made by Kyocera in Japan. Some are resin-impregnated silica materials, some are silica-impregnated silica (sic!) that can survive being fired in a kiln and still maintaining some ordering of silica nanoparticles that produces the play of color - hence the glass artists using it.

It boils down to semantics whether we call it 'opal‘ or something else - technically speaking it is an artificial material with opal-like structure and it displays opalescence. It would belong to a broad category of photonic crystals. Another example in this category are butterfly wings - again, the colors are due to periodic structures at the micrometer and nanometer scale, not due to pigmentation.

As far as I am concerned, the science of it, and the amazing skills and effort needed to produce such materials make synthetic opals a legitimate lapidary (or, more broadly, artistic) material. Goldstone is trivial by those same measures.

[VegasJames]

I disagree with the semantics part. By definition opal contains water. Therefore, if this does not contain water it is not really opal but rather a simulant.

For instance, I have also been playing with making turquoise. I can get a beautiful turquoise blue copper complex very easily, but without the aluminum component it is not turquoise no matter how much it looks like turquoise. Therefore, I add the aluminum component so that I end up with a hydrated copper aluminum phosphate, and thus synthetic turquoise. In this case it is a synthetic as it has the same chemistry of turquoise.  That is the difference between a synthetic and a simulant. A synthetic has the same chemistry as where a simulant does not have the same chemistry, bu=t looks the same. As a more specific example, moissanite (SiC) is a simulant of diamond (C) because they look very similar but are the same.