Can silk be faked??

[Pinkmartini87]

Dear all,

@T L gave me some food for thought in my last post and wanted to hear other experts chime in about this important issue also: can silk inclusions be convincingly faked in synthetic sapphires?

Case in point: Took my loupe to a $2000 small cornflower blue sapphire I saw in a pawnshop this weekend; this stone even visible to the naked eye and definitely under 10X magnification showed an abundance of silk. Is that enough to 1) Verify it’s a natural sapphire and not synthetic 2) Verify it was not high temp heated (because is it true some low heat will not damage the silk?)

Or will folks still advise in getting an AGL?

Thank you in advance for your thoughts.

 

[T L]

I always advise getting an AGL for expensive corundum because they trap a moment in time. Say in the future, there is a synthetic or invasive treatment that does not alter the silk in sapphires, and it’s hard or impossible to detect, you have a document claiming your stone was evaluated before the said treatment was being used. There used to be a time when silk meant no heat at all, and now that is not the case.

Irradiation is a good example of a treatment that is being used to alter color in some gems, and it’s almost impossible to detect. Old lab reports before the advent of this treatment are invaluable. For example, AGL recently discovered irradiation in emeralds that GIA missed.

I’m not saying ALL gems should get a lab report, but for those gem species with invasive treatments or highly deceptive synthetics, that are also pricey, it is advised. Rubies, sapphires, emeralds, diamonds, and some pricey spinels are top candidates. Ultimately, it is up to the consumer.

That sapphire you mention may be inexpensive enough to take the risk, but if it’s very pricey, I would insist on a lab report.

 

[Bron357]

In the olden days synthetic gemstones were totally perfect and that in itself was a telltale sign (apart from curved straie and minute gas bubbles).
These days you need to use a microscope rather than a Loupe to accurate see and assess inclusions. You’ve be amazed at the lengths and efforts some people will go to to pass off a man made gemstone as natural.
It’s because of the huge $$$$ in it!
But yes, there is a quenching process used with man made rubies and emeralds (and probably sapphires too) that creates the “look” of natural inclusions. Also undissolved flux can look a lot like natural inclusions too.
If the ring / sapphire is small / cheap you might like to take the risk, otherwise these days you need a lab report.

 

[Pinkmartini87]

@T L Think I’ll go for it! Not expensive.

@Bron357 Gosh, the ingenuity of these folks is almost admirable, minus the unethical lot of it all of course. I looked up some photos online of undissolved flux and quenching and so far neither looks like the inclusions I saw in the stone which are shorter, cleaner, more precise like small darts/arrows, unlike the more reticular/lurid/irregular “inclusions” with the two above methods, although I’m not sure if that’s anything to really go on since I’m an awfully new movie and I’m sure even experts have been fooled!

I do have a microscope at work, just a plain ol science laboratory microscope since I work in the medicine field. Would that work?

 

[Pinkmartini87]

Medical*

 

[Pinkmartini87]

Novice* not movie. Atrocious autocorrect today.

 

[Bron357]

I forgot but there is a man made star sapphire called a “Lindt Sapphire”. These gems have artificially introduced rutile to create the “star” effect, which is rutile (silk) catching the light and displaying as “white” against the coloured background. If you’ve ever seen a good natural star sapphire you appreciate better how “fake” a man made one looks.
Silk in sapphires is affected by heat, 99% of sapphires are heated to reduce the silk as that “whiteness” makes the gem appear milky.
Silk when heated breaks up, as are other natural inclusion crystal affected. A gemologist is trained to recognize these changes and transitions to determine, no, low or high heat.
Viewing a gem under a microscope effectively requires specific lighting ie dark field or spot led fiber optic as it’s often crucial to get the light source to highlight the inclusion. So a medical microscope can certainly magnify the inclusion (up to x100 is sufficient) but whether or not you have the appropriate light type and source to successfully view is ?
With a sapphire you would assume heated so the “silk” isn’t going to appear in a textbook appearance. Likewise feather inclusions from naturally healing fissures look very much like flux residue.
So it’s not beyond the novice but it’s not simple and straightforward to definitively determine natural low heat (acceptable and valueable) vs natural high heat and treated (whether by additives to heal fissures or beryllium to enhance color) and low value vs man made and low value. Highly treated “natural” is not worth much more than simple “man made”.

 

[Pinkmartini87]

@Bron357 Wow! Have you ever thought about putting together a guide or book, you know tons!

When I’m retired I hope attend gemology courses because all this is so fascinating to me!

Would underground heat result in low heat changes in a sapphire? One jeweler told me once that there’s enough “heat” when sapphires form naturally in the ground or when mined that sometimes silk can be broken up slightly just from that and can look just like man applied low heat treatment. Does that ring true to you, Bron? I need you to put the bogus meter to this one.

 

[voce]

@Bron357
Would underground heat result in low heat changes in a sapphire? One jeweler told me once that there’s enough “heat” when sapphires form naturally in the ground or when mined that sometimes silk can be broken up slightly just from that and can look just like man applied low heat treatment. Does that ring true to you, Bron? I need you to put the bogus meter to this one.

Not Bron here, but this is definitely not bogus. @PrecisionGem has mentioned before that some sapphires the Masai tribe in Tanzania dug out from the ground (volcanic terrain) test as heated. There is no way to tell whether the heat is natural or manmade, because heat is heat. Man emulates nature.

 

[Pinkmartini87]

@voce Thanks for the knowledge! Are sapphires typically found in heated/volcanic terrain, or are Tanzania sapphires an exception to the rule?

 

[voce]

@voce Thanks for the knowledge! Are sapphires typically found in heated/volcanic terrain, or are Tanzania sapphires an exception to the rule?

I'm not in the trade and haven't been on gem "safari"s, so I can't comment on what is true generally with any semblance of authority. I think the Tanzanian case is probably an anomaly, since when I saw how sapphires were mined in Montana and Sri Lanka in a video, it was a very different kind of mining, where the ground was not heated.

 

[T L]

I just saw a fake ruby online with silk. I’m not sure if it was a simulant or a new kind of synthetic.

I’m not advocating this site, and it’s supposedly a lab ruby. I just wanted to post for educational purposes. It came up in my social media feed. Obviously a ruby this size and price is fake, but if they’re doing this with lab ruby, I can see it with lab sapphire, and in more realistic sizes. There’s a video in the link to get a better perspective.

https://omojewelry.com/products/3-5...&utm_campaign=HT&utm_term=CE033&utm_content=V

 

[Pinkmartini87]

I just saw a fake ruby online with silk. I’m not sure if it was a simulant or a new kind of synthetic.

I’m not advocating this site, and it’s supposedly a lab ruby. I just wanted to post for educational purposes. It came up in my social media feed. Obviously a ruby this size and price is fake, but if they’re doing this with lab ruby, I can see it with lab sapphire, and in more realistic sizes. There’s a video in the link to get a better perspective.

https://omojewelry.com/products/3-5...&utm_campaign=HT&utm_term=CE033&utm_content=V

Thanks for sharing!! It’s crazy, and crazy easy to be fooled. I think I better let AGL handle it and not look through microscopes at stones myself and just keep my day job

 

[Pinkmartini87]

I'm not in the trade and haven't been on gem "safari"s, so I can't comment on what is true generally with any semblance of authority. I think the Tanzanian case is probably an anomaly, since when I saw how sapphires were mined in Montana and Sri Lanka in a video, it was a very different kind of mining, where the ground was not heated.

Thanks for your reply! I would love to go on a gen safari one day.

 

[suzanne2]

Thanks for sharing!! It’s crazy, and crazy easy to be fooled. I think I better let AGL handle it and not look through microscopes at stones myself and just keep my day job

I disagree!!! You are perfectly capable of seeing silk or no silk and making the first decision to either pass or send to a lab or buy on your instincts. Keep looking!

 

[Pinkmartini87]

@suzanne2 thanks for your kind encouragement! Well, maybe if I see textbook needle rutile I may take a chance to the great horror of my hubby who can’t comprehend my fascination with stones...although I suppose the imposters can get pretty close to even the textbook real deal.

 

[T L]

I disagree!!! You are perfectly capable of seeing silk or no silk and making the first decision to either pass or send to a lab or buy on your instincts. Keep looking!

I respectfully disagree. One should never buy any expensive sapphire, ruby, emerald, or diamond on instincts. I would let the professionals look it over instead.

 

[suzanne2]

I got a little ahead of myself. "Making the first decision to pass or send to a lab" and I should have stopped there. I agree, I would never buy an expensive stone without a lab report, but there are lots of inexpensive stones out there to look at...Sorry, I should be more careful with my wording. Practicing with lots of inexpensive stones is how I gained confidence in my eye and I like to encourage others to do the same.

 

[Pinkmartini87]

@suzanne2 just wanted to say I love the sapphire halo in your avatar! A striking contrast between the green and blue.

 

[pearlsngems]

I forgot but there is a man made star sapphire called a “Lindt Sapphire”. These gems have artificially introduced rutile to create the “star” effect, which is rutile (silk) catching the light and displaying as “white” against the coloured background. If you’ve ever seen a good natural star sapphire you appreciate better how “fake” a man made one looks.
...

I think autocorrect got you! I'm sure you were trying to type Lindy, not Lindt.

 

[Frost]

It really depends on the stone but generally speaking no, silk has never been and as of now cannot be convincingly faked in sapphires. The key word is convincingly - meaning you have to know what you're looking at. And if you do, then there's just no way on Earth that you can mistake actual natural silk for flux or cracks or anything of the sort in a synthetic instead.

The ruby posted above is a good example of something that looks like silk, but isn't - these have been available in large quantities in Thailand and elsewhere for a long time now. I can't be 100% sure just looking at a link, but I think there's a pretty good chance that they may have actually labeled it wrong - it looks exactly like glass-filled, rather than lab-created.

Regarding heat - no temperature 100% guarantees silk removal, so some silk is never a guarantee of an unheated stone (to the contrary, quite a few keep some microscopic fields of broken down rutile silk after heating). And irrespective of whether the stone has been just blowpipe heated or nearly melted in a furnace, some silk may remain - with Sri Lankan or Madagascan stones for example you'll occasionally see a great improvement in clarity after heating, but with Mozambique or Cameroon ones you sometimes won't - and even after heavy heating they'll still look silky and dim.
No heat differs from unheated under the microscope enough to get a pretty clear idea of whether a stone has been heated or not, but I wouldn't trust a microscope for a final word on that so a lab report is always a better idea when anything is claimed to be (or looks) unheated. Low heat, that may not register 100% clearly as heated under a microscope, is still heat and still should be bought/sold as heated.

Oh and yes, sapphires can actually register as 'low heated' straight out of the ground - albeit it's very, very rare, at least with Asian localities. If it does happen, well, it's unfortunate but it has to be sold as heated, of course. It's rare enough not to really impact anyone's bottom line though.

 

[Pinkmartini87]

@Frost Thank you for taking the time to write such a thorough explanation, which ties up this entire thread nicely and answered all my questions. I’m very appreciative!!