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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.

[vitzitziltecpatl]

Those are indeed the definitions of synthetic/simulant/natural materials.

Unfortunately, VegasJames, most people will never bother to learn about these sorts of things. Bugs me sometimes, too.

One of the funniest things I've ever seen was a big-box jewelry dep't sign in a case with their "Genuine Lab Created Opal"... .

[R.U. Sirius]

I appreciate the nuance of synthetic vs. simulant, but I find it irrelevant in practice - be it for the consumer, or for the artist. Laboratory-grown materials are of course different from naturally occurring materials in many practical ways, (cost, consistency in properties, dependance on proprietary processes), and should be disclosed as such.

The synthetic vs. mere simulant distinction, however, depends on how hard we look, and how much we are willing to spend on instruments. Naked eye, loupe, microscope, refractometer, Raman spectrophotometer, FT-IR, electron microscope, trace element analysis, isotope analysis, XRD - eventually, you will find a difference, no matter how small, between the synthetic and the natural material, and thus the "synthetic" will suddenly become the "simulant". There is no objective distinction between the two categories, it simply depends on our technical ability. All lab-grown materials are either simulants, or completely novel materials that never aimed to simulate a natural material (goldstone, for example).

[VegasJames]

I appreciate the nuance of synthetic vs. simulant, but I find it irrelevant in practice - be it for the consumer, or for the artist. Laboratory-grown materials are of course different from naturally occurring materials in many practical ways, (cost, consistency in properties, dependance on proprietary processes), and should be disclosed as such.

The synthetic vs. mere simulant distinction, however, depends on how hard we look, and how much we are willing to spend on instruments. Naked eye, loupe, microscope, refractometer, Raman spectrophotometer, FT-IR, electron microscope, trace element analysis, isotope analysis, XRD - eventually, you will find a difference, no matter how small, between the synthetic and the natural material, and thus the "synthetic" will suddenly become the "simulant". There is no objective distinction between the two categories, it simply depends on our technical ability. All lab-grown materials are either simulants, or completely novel materials that never aimed to simulate a natural material (goldstone, for example).

Again I disagree. The definition of synthetic when it comes to stones is having the same chemical makeup but being artificially made. Therefore, a synthetic ruby/sapphire is still a synthetic regardless if it has the same crystal structure or refractive index.  For instance, flame fusion rubies are cooled so rapidly that they do not form much of a crystal structure unlike flux or hydrothermal grown rubies. Yet all three forms of rubies are still synthetics.

Simulants on the other hand have the look of a particular stone but not the chemistry. For example, red glass can, which is silicon dioxide, not the aluminum oxide of ruby/sapphire, could be used as a ruby simulant as it has the look but not exact chemistry of ruby. Plastics made to look like opal would be opal simulants, not opal. By the same reasoning, synthetic opal would have to contain a percentage of water as part of its chemistry to be considered synthetic. Otherwise, it is more like a glass, especially if fused by heat, and thus would be an opal simulant.

[R.U. Sirius]

Got it - the distinction is in chemical composition and crystal structure (ignoring trace impurities, isotopes, inclusions, crystal growth patterns, etc.).

[VegasJames]

Got it - the distinction is in chemical composition and crystal structure (ignoring trace impurities, isotopes, inclusions, crystal growth patterns, etc.).

How can trace impurities be ignored when they can define a stone? For example, ruby and sapphire are both aluminum oxide. In fact, rub is just red sapphire. The name of the stone depends on the color due to trace impurities. Same with things like variscite and turquoise, and others which are aluminum phosphates. They are still different stones bases on trace impurities present. And what about the different forms of quartz such as amethyst and citrine, which are named due to their trace impurities that can give them different colors. Same with the beryls such as emerald, red beryl, aquamarine, maxixe, heliodor, etc. that are all separated by their trace impurities.

[R.U. Sirius]

Right, that's exactly why I originally stated that you can always, in principle, distinguish between lab-grown and natural stones - it's just a matter of how hard you look, with what precision, and with how many analytical techniques. Therefore, the claim that "synthetic stones are identical to natural counterparts in chemical composition" is a moot point - I guarantee that, eventually, I will be able to find a difference in trace elements, isotopes, etc.

We stray far from the original topic here, and it doesn't really matter, as long as we know what someone is frying to say when they say "synthetic" or "simulant" - but my point is that one shouldn't have strong opinion, as synthetics will never be truly "indistinguishable" from the natural material.

[VegasJames]

Right, that's exactly why I originally stated that you can always, in principle, distinguish between lab-grown and natural stones - it's just a matter of how hard you look, with what precision, and with how many analytical techniques. Therefore, the claim that "synthetic stones are identical to natural counterparts in chemical composition" is a moot point - I guarantee that, eventually, I will be able to find a difference in trace elements, isotopes, etc.

We stray far from the original topic here, and it doesn't really matter, as long as we know what someone is frying to say when they say "synthetic" or "simulant" - but my point is that one shouldn't have strong opinion, as synthetics will never be truly "indistinguishable" from the natural material.

We can find all sorts of differences in the same types of various natural stones. Diamonds can have different crystal structures different impurities, and can even have vacancies in the crystal lattice.  Beryls, calcite and various other stones can have various crystal structures. I have found various forms of gypsum as selenite, satin spar, and alabaster in numerous different crystal structures and in various colors (white, red, blue, green, golden, tan, dark brown). And not all stones have crystal structure. There are around 300 types of opal, most of which are completely amorphous. Therefore, crystal structure is pretty much irrelevant. Although, Len Cram I mentioned earlier is producing precious opal that cannot be distinguished from naturally occurring opal.

Opal can also vary a lot in chemistry. Even though all opal contains amorphous silicon dioxide and water, it can also contain a lot of other things. These include crystalline silica, aluminum oxide, uranium, cinnabar, sodium, potassium, carbon, lithium, cobalt, thorium, iron, magnesium, barium, titanium, vanadium, copper, manganese, zinc, nickel, etc.

So getting back to my original point, a synthetic is not based on impurities or crystal structure. A synthetic is a stone that has the same chemistry and form as the base stone. As where a simulant is not the same as an synthetic. A simulant is a substance that has the appearance of the real thing, but without the same chemistry. Therefore, your claim of "eventually, you will find a difference, no matter how small, between the synthetic and the natural material, and thus the "synthetic" will suddenly become the "simulant". There is no objective distinction between the two categories," is incorrect. If we go by your definition then we would have to conclude that amethyst and citrine are quartz simulants since they differ compared to a natural pure quartz crystal.

[irockhound]

I agree and think that is the best description of the differences between simulant and synthetic materials.