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Dealing with Amethyst Synthetics

Hi all,

Just joined this forum and was wondering about Amethyst and what inclusions it has as natural and synthetic to be able to tell the difference?

Not sure if there is a resource for this.

I am doing recuts of some cheap amethyst purchased as second hand gems and I would like to be able to tell the difference if possible.

Have refractometer, microscope and polariscope etc for testing.

Any thoughts on this or do you still really need a lab to tell synthetics if no inclusions are visible?

Thanks in advance

Hi Nicholas,

Welcome!

I am just gearing up for my GIA Coloured Stones exam so I’ve got that info right here… Without quoting my course materials verbatim, here’s the gist: Quartz was first commercially synthesized in the 1950s. In the 1970s synthetic amethyst using the hydrothermal method entered the market (grown on untwinned seed crystal). Prices plunged because consumer confidence was shaken. At that point standard gemological equipment could be used to detect synthetics. But, in the 1990s producers began using twinned natural seed crystals, which makes it extremely difficult to separate natural from synthetic. Advanced gemological testing would be required.

It’s also mentioned that much of the jewellery industry ignores the issue of synthetic amethyst detection and disclosure (as reported by trade publications) and theorise that it’s because of the expense of testing and that the prices of both materials are fairly low.

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Wendy is correct – the price of synthetic quartz vs. natural quartz is pretty much the same. Since both materials are very common in the gem market with almost no one willing to pay a premium for advance testing, there is no financial incentive to figure out which is which.

The only way I am confident I have natural quartz is if I cut it myself from the rough. In the rough, it is not difficult to tell natural from synthetic when there is crystal structure evident. (Though, I suppose, synthetic could be made to look like natural, but given the prices there is no point for tricksters in doing this).

Whoever purchases the finished stone must rely on the cutter’s honesty. Like so many other parts of our industry, it again comes down to trust.

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Thank you for the information from you both.

Is there a resource which gives the inclusions found in natural and synthetic amethyst to compare them?

If I am buying cut stones to recut, then to have a way to determine synthetics, even if not guaranteed, would be useful. I would prefer to only deal in natural materials as much as possible and I will be selling cut gems via ebay until I build up a reputation. The following image is an amethyst I have finished cutting as an example.

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Nice :+1:

Good luck with your venture.

I’ve searched around online and really don’t have an answer. Some articles talk about colour zoning, but I wouldn’t rely on that too much.

Articles from the likes Gem-A and GIA would be your most reliable source. The only GIA article I found was from 1986…

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First off: “Wendy is correct – the price of synthetic quartz vs. natural quartz is pretty much the same. Since both materials are very common in the gem market with almost no one willing to pay a premium for advance testing, there is no financial incentive to figure out which is which.”

NO: Synthetic amethyst is MAXIMUM $1ct (if you want 20000cts, you can get it as cheap as $0.30ct, probably less). Fine quality Uruguayan amethyst starts at about $15-$20 USD/ct, and that is for parcels, dealers in NYC are selling the best qualities for $40-$50ct for single gems.

Amethyst prices have been rising (like all gems), a friend said to me about a decade ago: “We are going to find out how much synthetic amethyst is around when it gets expensive enough for people to start getting certs on it” Well, we are getting there already (disclosure, this is my site): https://skyjems.ca/collections/certified-gemstones/amethyst

Now, onto detecting natural from synthetic… Almost all natural amethyst has at least SOME zoning to it.

SOME synthetics do, but, the zoning is perfectly straight and obviously not natural. Also, no banding of color.

So… the quick and dirty way to check is put it in a white bowl with water in it, table down. If there is no zoning, you have a ‘more testing required’ situation. If there is ‘flowing’ zoning through the gem, you are almost certainly good.

GOOD LUCK!

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Nice cut job. The only wat to know for sure is to get your stones from the natural rock its self. I have a nice size one laying around here some place that I would love to have a stone cut out of some day but I am not sure of the quality of the colors. You would be welcome to it if you could find a nice stone to cut out of it for me. It has quite a few thousand carats in it. I will send a picture of it to you as soon as I locate it. I have it packed away right now.
All the best.
Otter.

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Where dat picture?

:purple_heart: Thank you for polishing up the tone of this thread. I was rather hoping someone would. You are a gem.

Thank you all for your input.

Otter, I don’t have the facilities for a stone of that size. You would need a trim saw, possibly a slabbing saw depending how large the piece was, and probably 8 inch laps minimum.

I am happy doing smaller 1-10ct stones and selling them via ebay for now. Just need to build up a reputation.

The idea that prices of synthetics and natural amethysts are the same, is one that should not continue to be taught.

With enough experience a polariscope will more than often give you enough evidence of its natural vs synthetic origin. As a laboratory, we can attest that, while the concept of experimentation of twinned synthetic growth is possible; it has not been a practical method of growth. We have as yet to come across a twinned synthetic amethyst after having tested hundreds of amethyst. BTW, we will also use FTIR (infrared spectroscopy) to backup our tests.

Thanks for the note about the twinning! I have had other gemologists tell me basically the same thing.

As I understand it though, about 5-10% of natural amethyst don’t have twinning.

Have you tested natural stones with no twinning?