Uncertified stones?

[Arcadian]

There are stones I won't buy without a report. @PrecisionGem is right that it does add to the cost. But for peace of mind, I will do it. The biggies are Sapphires, Rubies, and copper bearing tourmaline. (I will not buy copper bearing tourmaline anymore without a report of some type)

The rest I do home testing for baseline, then get a gem brief if I think its warranted for my own curiosity.

 

[chrono]

Add red spinel to that list of big gems (paraiba, ruby, blue sapphire, padparadscha, emerald) I don't feel comfortable buying without a lab confirming the treatment or lack off. My price point for confirmation of these gems is around the $500USD mark or 1 carat, whichever one applies first.

Edited grammatical errors because I can't stand looking at them!

 

[voce]

Corundum probably undergoes more invasive kinds of treatment, as well as synthesis, than any other gem I can think of. I once paid more for a lab report than I did for a whole stone (sapphire), and I’d do it again in a heartbeat. My stone was undervalued by the vendor, but I wanted peace of mind.

You have to remember that most labs around the world have the ability to test for heat, but not necessarily for all kinds of chemical enhancement. I had to pay an extra $100 for that, Therefore it’s not even good enough to buy corundum with the lab report, it has to come from a highly reputable lab that has the ability to do these tests.

Just because the labs might have missed something, I'd rather buy unheated to have peace of mind even if a sapphire is stated to be heat-only in a report.

 

[minousbijoux]

[QUOTE="T L, post: 4696564, member: 33940”]

You have to remember that most labs around the world have the ability to test for heat, but not necessarily for all kinds of chemical enhancement. I had to pay an extra $100 for that, Therefore it’s not even good enough to buy corundum with the lab report, it has to come from a highly reputable lab that has the ability to do these tests.
[/QUOTE]

Yes, I omitted the obvious - a lab report from one of the top labs with the requisite equipment. Here, that would be AGL or GIA.

 

[Frost]

I've been wanting to avoid another beryllium tirade (a year after the last), but there's a bit of misinformation being spread on here about it so I just thought I'd pitch in. My intent is not to dissuade PSers from using or recommending their preferred labs - because they are good labs and that's a definite fact - but I do want to get some facts out and hopefully help both sides bridge their misunderstandings. Facts sometimes seem to get lost here in what at times almost looks like diffusion paranoia.


I'm sorry but to say that “only a few select labs with equipment” can reliably detect diffusion in corundum is simply and plainly wrong. I'm just an FGA/GIA alumni and I definitely don’t consider myself a gemologist at all since I don’t practice but people, please understand that diffusion isn’t rocket science!

Anyone with knowledge and an FTIR + LIBS + microscope should be able to detect it. And before someone mentions this, another point – the vast majority of labs, "recognized ones" included, do not use laser ablation (LA-ICP-MS) to test your gems for diffusion. Please go have a sit down with them and ask them. The reason why is that it simply is not routinely necessary to detect beryllium in sapphire at all, not even close.
I understand that some forum members have had bad experiences with this in the past and I do think that is truly regrettable - and the actions of those sellers, if on purpose, are absolutely inexcusable.
But please don't paint the entire gem $23 billion gem trade with the same brush because you came across a bad $1,000 egg and now everyone else apparently stinks too. It's not factual and it's not accurate.

GIA for example uses laser ablation mainly to type-check new sources and finds: they use it to fill their database with extremely thorough chemical measurements of corundum found in various sources, so that they’d be able to all the better pinpoint where subsequently tested stones came from (since origins tend to share chemical data to a degree).
They sure as anything don’t use it to check for beryllium in hundreds or thousands of tiny corundums they issue reports for daily - do you even have any idea of how much these reports would cost and how long they would take to complete if that were the case? If they did, how would they be willing and able to offer you on-site testing for heat and diffusion at whichever gem show you want (Asian ones included) and give you a report in a few hours? You, and a hundred other people waiting in line too?

I’ve seen some recent claims/warnings to posters on PS where members have said that basically any vivid blue, vivid orange, pad etc. should be suspect and this is plainly false.

Scaremongering and bits and pieces of information stated as facts don’t benefit the people posting here looking for advice, and they don't reflect well on this forum in the long run either. The only people it benefits is labs. Please remember that labs are also businesses (far better businesses than gem trading, and fair enough, they work very hard too) with their own self interests first and foremost – so before naively repeating the same things, please do some research. Better yet, travel, see the world, see and understand how the trade works and you'll be much better off for it.

I’ll say this part flat out – as great as GIA and AGL are, no, they are not the only labs on the planet capable and equipped to handle beryllium. There are many decent labs all over the planet with the money and experience necessary for the equipment, it's pretty much a requirement to be even called a lab at all nowadays. And they can, and do, detect corundum enhancements regularly and accurately.

Am I crazy, or do people sometimes think that these "third world countries" test stuff by rubbing sticks together in some jungle somewhere, or don't have the cash on hand for instrumentation?

How on Earth, when there's a ton of gem dealers all over the place - ones that you will not see come online for another 20-30 years, if even then - with tens or hundreds of millions of $ in stock? Please go and visit Burma and Sri Lanka, have a coffee in one of their offices and see for yourselves how "impoverished" and "uneducated" the gem trade is. You'd be very surprised.
It's funny, you know - the Western tourist often thinks that gems are bought for a bag of rice locally from someone who doesn't know any better, and the Eastern seller often thinks Westerners are walking ATMs who don't know any better. Both are ignorant, both are completely wrong and both approaches lead nowhere.


If someone thinks I’m wrong about diffusion, please explain to me this: we have seen thousands of sapphires go to trade and non-trade clients all over the planet in these past xyz years. The vast majority that went to dealers or jewelers in the U.S. or Canada got a GIA or AGL lab report subsequently, since the dealers understandably require those reports for the local market.

How is it possible, with the supposed omnipresence of beryllium and total incapability of “non-trusted labs” to detect it, that we have never once seen a return due to enhancement discrepancies? How is that possible, since we have seen some top of the line stones which, according to some info I’ve seen on here, should be highly suspect? But to be fair, I'm not talking about some shady eBay-ish stuff.

The reason there weren’t any discrepancies is simple – diffusion isn’t rocket science like it was when the trade and labs scrambled to come to grips with it in 2000s. You will be able to tell that a stone has had extremely high heat applied to it because it will show up under a microscope and the FTIR. There is no "blowpipe heating diffusion" at 900 degrees Celsius. So when you see evidence of high heat, then you'll also know which stones are highly suspect and which stones should be sent for LIBS testing too (as well as any additional tests).


I am not saying to trust labs blindly... The opposite, in fact. Do trust only the labs you want to trust, peace of mind with your stones is everything. But when any gem lab anywhere tells you “we’re the only ones capable of detecting this”, please take it with a grain of salt and understand that isn’t so much scientific reality as it is good marketing. I understand that they need to market themselves and don't begrudge them, it is what it is - but please don't spread panic and misinformation when there is no actual, real need for it.

I appreciate the posters on here and all the informative, well-meaning, useful advice given out on a daily basis. And I'm not trying to open a can of worms or ripple the pond people, I just wanted to get a few facts out that are for some reason being overlooked. I'm writing this in hope that everyone can better understand each other and work together with as few bad experiences as possible and without having to live in fear that isn't actually warranted as much as it may seem.

 

[Rfisher]

So how do you feel about returns, @Frost ?

 

[jordyonbass]

As an Opal seller in Australia, this is a really tricky thing for me as between my price point in the market as well as my distance from a reputable gem lab, it just isn't worth doing lab reports for my Opals - yet I've had some requests for lab reports. But the rabbit hole goes so much deeper than that when it comes to the issues with sending Opals to reputable gem labs from what I have heard

 

[Frost]

So how do you feel about returns, @Frost ?

Don't feel much, never had any, heh.

In all seriousness though, if it has to be done it has to be done, there's nothing to it. It's the cost of doing business.

The best you can do as a seller is to get informed, know the lab you're dealing with, know their methodology, know gemology as well, know your sources and the chain of custody and you're on the right track already.

Gems are marketed worldwide, there's no one I know of who markets them to one particular continent. So what do you do? Buy a stone and send it to AGL for the U.S., SSEF/Gubelin for Europe and GRS for East Asia just so you can offer everyone what they want? Feasible for $500,000 pieces at Christie's, not feasible for the majority.

Your best bet is to basically know who and what you're dealing with, produce lab reports you personally after careful evaluation can trust, and then of course offer people the chance to take the stones to any lab of their own choosing and refund them in full (including lab report charges) if there are enhancement discrepancies in the reports.

Beryllium vs. no beryllium isn't a minor difference of opinion, it's sacrilege and the difference between a gem and a worthless trinket - so yeah, I think reports should get refunded too in cases like that. But I do understand that not everyone agrees on that, as some sellers see it as a waste of time for a stone that they'd sell without any issues and extra legwork otherwise. Comes down to what your market wants I guess.

In other cases, like geographical origin, it gets a bit sketchier because labs do differ on that quite a bit. There are cases where you can be 100% sure a sapphire is Sri Lankan and lo and behold, a well known lab says "Myanmar". Ehm, nope. Or someone pulls something out of a mine in Madagascar and two weeks later in BKK they say "Sri Lanka". And we've also seen a case where the exact same big teal tourmaline had two different origins from the same reputable lab (two reports, a few months apart from each other and made in different locations). So for origin, I don't know - you can be honest and thorough and give it your best shot I suppose. Pretty much what the labs themselves do too.

This doesn't go for ultra-premium origins like Burma and Kashmir, of course - in those cases you either get lab consensus or you don't pay for it.

 

[LilAlex]

Please go and visit Burma and Sri Lanka, have a coffee in one of their offices and see for yourselves how "impoverished" and "uneducated" the gem trade is. You'd be very surprised.
It's funny, you know - the Western tourist often thinks that gems are bought for a bag of rice locally from someone who doesn't know any better, and the Eastern seller often thinks Westerners are walking ATMs who don't know any better. Both are ignorant, both are completely wrong and both approaches lead nowhere.

Helpful post -- thank you! My fear is not that a "third-world" vendor would unknowingly pass off a treated stone; it's that they would do so knowingly. This has been happening for centuries. First-world, too!

 

[LilAlex]

There are cases where you can be 100% sure a sapphire is Sri Lankan and lo and behold, a well known lab says "Myanmar". Ehm, nope. Or someone pulls something out of a mine in Madagascar and two weeks later in BKK they say "Sri Lanka". And we've also seen a case where the exact same big teal tourmaline had two different origins from the same reputable lab (two reports, a few months apart from each other and made in different locations). So for origin, I don't know - you can be honest and thorough and give it your best shot I suppose. Pretty much what the labs themselves do too.

This doesn't go for ultra-premium origins like Burma and Kashmir, of course - in those cases you either get lab consensus or you don't pay for it.

But Myanmar is Burma, yes?

 

[Frost]

Helpful post -- thank you! My fear is not that a "third-world" vendor would unknowingly pass off a treated stone; it's that they would do so knowingly. This has been happening for centuries. First-world, too!

Absolutely agreed. But what I was trying to convey is that Be diffusion isn't as prevalent, widespread or impossible to detect as reading this forum would sometimes make it seem. That relates directly to lab capabilities, rather than the honesty of the sellers.
Because if a seller has a valid non-fake report, they can only repeat to you what a lab has already concluded. Labs exist so the honesty of the sellers can be taken out of the equation regarding treatments.

Honesty regarding color, clarity etc. is a different matter though.

Of course one should be careful ordering from abroad, I absolutely agree with everyone else on PS on that. People are cautious about it because of a lack of recourse.

So the best advice I could come up with is to order in such a way that you always retain some leverage. If you're ordering from someone with exposure, an online presence, a track record, hundreds of clients other than you etc. - and then even if to be on the safe side you assume they are really bad people with absolutely no concept of morality or integrity - you can at least to some degree bet that it will be in their own self-interest not to be shortsighted enough to risk their reputation and livelihood over any single deal.

Whereas when you order from an unknown Instagram, eBay or Facebook seller hawking stones which in some cases aren't even their own, there's very little recourse when things go wrong. There are known ones too, and PS usually points them out.

Of course, double-check online if the report is correct before you pay... And then make another report when you get the stone, if that is necessary.

But Myanmar is Burma, yes?

Yes, but I think there was a misunderstanding - I was talking about a case where we sold one of our own 100% Ceylon stones to a foreign dealer. It was bought 2 minutes' walk from a mine in Elahera, Central Sri Lanka. A year later, we were told - quite happily too - that a 'big name lab' issued a report for it as Burmese.

So what they would need to do in that case is clearly communicate to their buyers that the lab report is wrong, rather than go and try to make a few other labs agree that it might be Burmese.

If on the other hand a different stone truly is Burmese, then sure, you should get other labs to agree since there's a huge price difference.

I was trying to say that labs sometimes make mistakes in giving premium origins to stones that aren't - but when one is 100% sure of premium origin and that is being priced in, they need to produce valid lab proof of that. The higher the price, the more different labs agreeing on it you need.

The whole origin thing is a little bit strange in my opinion.... Elahera in Sri Lanka and Bemainty in Madagascar have produced sapphires identical in appearance to Kashmir in the past.* The same two places (as well as others) have also produced Burma dead ringers.
So, the idea of paying 1,000% or 2,000% more buck for the same bang... To get a real Kashmiri that looks just like a non-Kashmir one... I don't know. But fair enough, the collector market is a different universe I guess.

*
1) https://www.ssef.ch/wp-content/uploads/2018/06/2017_Krzemnicki_sapphire_Bemainty_InColor.pdf

2) https://www.gemstone.org/incolor/Incolor19/index.html#33 ("Kashmir-like", p. 33)

3) https://www.ssef.ch/wp-content/uploads/2018/01/2013-Krzemnicki-Kashmir-sapphire-Facette.pdf ("subtle differences", p. 7)

4) https://www.gia.edu/doc/The-Elahera-Gem-Field-in-Central-Sri-Lanka.pdf ("comparable to the well-known Kashmir blues", p. 85)

 

[Bron357]

One problem is who can you trust other than the “known” labs?
I shop on eBay and Etsy and I see a lot of gems with “lab certificates” that can’t possibly be genuine given the price. If the price was a lot closer to an expected price I could be fooled.
I’m sure there are reputable gem labs in China, India, Sri Lanka etc but how do I know which ones they are? Scammers even fake genuine lab certificates these days.
When you’re buying online you’re buying on the basis of a few photos / videos. Some of these gems are thousands of dollars. That’s a lot of money to send off to a person on the other side of the world. So to feel safer we look for vendors others have used before us and been happy with. To feel confident that the words will match the gem we look for lab reports from a source we have heard the name of before. That’s not to say other labs or other vendors aren’t totally trustworthy and accurate but given so many aren’t and it would be very upsetting to be conned out of a large sum of money most of us prefer to stick with what we feel we know and can trust.

 

[Frost]

One problem is who can you trust other than the “known” labs?
I shop on eBay and Etsy and I see a lot of gems with “lab certificates” that can’t possibly be genuine given the price. If the price was a lot closer to an expected price I could be fooled.
I’m sure there are reputable gem labs in China, India, Sri Lanka etc but how do I know which ones they are?

I can completely relate because that's exactly what we do too. We trust our suppliers, but the deal is only ever considered "done" once a lab we trust confirms everything is as declared. Which can sometimes take months due to logistics - so we pay, but under the condition of a full refund if there are any discrepancies.

My issue is that I don't unfortunately have any way of telling people on here things exactly the way they are, and which labs can be trusted, because I'd probably be breaking a few forum rules in the process. It wouldn't sound impartial and it would look like marketing - which is not my purpose here. We even declined to link our company name/site in the sig because I don't want my posts on here to be thought of in any way as self-serving when the actual intent is to discuss very real and important issues.

So I could more generally speaking say that there are two labs in Sri Lanka that do have the equipment and a consistent track record. Even then, we only trust one single lab (the one we found to be the most traditionalist, rigorous and reserved; the least of a sellout, to be blunt).

Reasons: they have the equipment, they don't throw around trade terms like candy, and the owner is a perfectionist concerned more with reputation than profit (so yes, gem dealers shouting "how is this not royal blue!" or "it's unheated!" happens in the lobby every so often but the important thing is that they don't budge). Also, they don't issue a report when they aren't 100% certain - so if a stone does not have a single natural diagnostic inclusion under the microscope, even when the advanced machinery readouts look good, they word it as inconclusive and don't issue papers for fear of new synthetics. We famously failed to get a report for a sub-1 carat hessonite (yes, hessonite) which was microscopically clean. It was a hessonite 100% but they were too scared of saying that just in case someone came up with synthetic garnets in the meantime and gemology hasn't caught up yet (so it'd make them look bad 10 years down the line).

I'd also like to point out that there are a few labs in Sri Lanka which scammers specifically and purposely go to to get trade terms and misidentifications. Those are paper shops, not even worth the paper they're printed on, and they damage both legit labs and dealers immensely. We've seen cases of spinel being identified as "unheated padparadscha" (it takes 30 seconds on a refractometer to say otherwise), synthetic white sapphire (Verneuil, curved growth! The easiest to spot of all) called "unheated", 20% change chrysoberyls being called "alexandrite", brown/orange/yellow sapphires being called pads etc. And similar horror stories, but never from legit labs.

Can't speak for India, Africa etc. And Thailand has no shortage of good options.

Those are glaringly obvious scams, no need to even consider reports. I'd not even look at eBay for good stones because 99% of the time if you see a "good" stone on it, there's a reason it's selling on eBay to begin with. Windows, humongous pavilions, inclusions, treatments etc. I don't mean known sellers though, of course there are good dealers who just happen to list on there as well as other places.

Scammers even fake genuine lab certificates these days.

Short of access to a lab's website hosting credentials and database, impossible - because you verify the report ID online and it either checks out or doesn't (or otherwise, you give them a ring directly and ask).

 

[icy_jade]

I can completely relate because that's exactly what we do too. We trust our suppliers, but the deal is only ever considered "done" once a lab we trust confirms everything is as declared. Which can sometimes take months due to logistics - so we pay, but under the condition of a full refund if there are any discrepancies.

My issue is that I don't unfortunately have any way of telling people on here things exactly the way they are, and which labs can be trusted, because I'd probably be breaking a few forum rules in the process. It wouldn't sound impartial and it would look like marketing - which is not my purpose here. We even declined to link our company name/site in the sig because I don't want my posts on here to be thought of in any way as self-serving when the actual intent is to discuss very real and important issues.

So I could more generally speaking say that there are two labs in Sri Lanka that do have the equipment and a consistent track record. Even then, we only trust one single lab (the one we found to be the most traditionalist, rigorous and reserved; the least of a sellout, to be blunt).

Reasons: they have the equipment, they don't throw around trade terms like candy, and the owner is a perfectionist concerned more with reputation than profit (so yes, gem dealers shouting "how is this not royal blue!" or "it's unheated!" happens in the lobby every so often but the important thing is that they don't budge). Also, they don't issue a report when they aren't 100% certain - so if a stone does not have a single natural diagnostic inclusion under the microscope, even when the advanced machinery readouts look good, they word it as inconclusive and don't issue papers for fear of new synthetics. We famously failed to get a report for a sub-1 carat hessonite (yes, hessonite) which was microscopically clean. It was a hessonite 100% but they were too scared of saying that just in case someone came up with synthetic garnets in the meantime and gemology hasn't caught up yet (so it'd make them look bad 10 years down the line).

I'd also like to point out that there are a few labs in Sri Lanka which scammers specifically and purposely go to to get trade terms and misidentifications. Those are paper shops, not even worth the paper they're printed on, and they damage both legit labs and dealers immensely. We've seen cases of spinel being identified as "unheated padparadscha" (it takes 30 seconds on a refractometer to say otherwise), synthetic white sapphire (Verneuil, curved growth! The easiest to spot of all) called "unheated", 20% change chrysoberyls being called "alexandrite", brown/orange/yellow sapphires being called pads etc. And similar horror stories, but never from legit labs.

Can't speak for India, Africa etc. And Thailand has no shortage of good options.



Those are glaringly obvious scams, no need to even consider reports. I'd not even look at eBay for good stones because 99% of the time if you see a "good" stone on it, there's a reason it's selling on eBay to begin with. Windows, humongous pavilions, inclusions, treatments etc. I don't mean known sellers though, of course there are good dealers who just happen to list on there as well as other places.



Short of access to a lab's website hosting credentials and database, impossible - because you verify the report ID online and it either checks out or doesn't (or otherwise, you give them a ring directly and ask).

@Frost can you pls share the names of the two labs in Sri Lanka and which one in particular you trust?

On another note, should we have a sticky for trusted labs? And perhaps those of us who are based in those countries or have experience dealing with those labs can comment or share our knowledge?

Completely agree that there are Asian labs that can be trusted. But trade terms wise... honestly I’ve seen so many dubiously named gems even from VERY reputable labs that I think is still best to trust your own eye.

 

[T L]

@Frost can you pls share the names of the two labs in Sri Lanka and which one in particular you trust?

On another note, should we have a sticky for trusted labs? And perhaps those of us who are based in those countries or have experience dealing with those labs can comment or share our knowledge?

Completely agree that there are Asian labs that can be trusted. But trade terms wise... honestly I’ve seen so many dubiously named gems even from VERY reputable labs that I think is still best to trust your own eye.

I don’t trust some well known Asian labs to rule out any possible diffusion in corundum. However, for everything else, they can be fine.

 

[Lilith112]

@Frost can you pls share the names of the two labs in Sri Lanka and which one in particular you trust?

On another note, should we have a sticky for trusted labs? And perhaps those of us who are based in those countries or have experience dealing with those labs can comment or share our knowledge?

Completely agree that there are Asian labs that can be trusted. But trade terms wise... honestly I’ve seen so many dubiously named gems even from VERY reputable labs that I think is still best to trust your own eye.

I think GRS' trade terms are particularly...dubious. I saw a looot of "padparadschas" that were either only pink or very brown. I'm also not entirely sure I trust in GIA's color assessment at times.

Regarding Asian labs, my understanding is that Singapore's Nanyang Lab is quite stringent and reputable, even if it's not that well known-- same thing applies for Lotus Lab. I've also heard good things about AIGS.

In general, I think the most basic thing a seller should offer is an additional report opened with your lab of choice as well as a return policy if the results don't match up. A good seller will know the value of his/her gems and will certify accordingly to bolster its selling point.

 

[T L]

AIGS could not properly test my sapphire for diffusion. I had to end up sending it to AGL.

 

[T L]

I think GRS' trade terms are particularly...dubious. I saw a looot of "padparadschas" that were either only pink or very brown. I'm also not entirely sure I trust in GIA's color assessment at times.

I agree here, especially GRS, They cater to vendors in their liberal assessment of color. Everything seems vivid or pigeon blood.

 

[PrecisionGem]

Even the well know and respected labs get things wrong.

I cut these small rubies/sapphires from Lake Baringo in Kenya from time to time. The stones are found by the local people after the rains. They are not heated or treated, yet I have had a stone that a customer sent to the AGL, and they reported it as heated. I bought the stone in Africa, from the guy who picked it up. I told him I am buying your stones no matter what, I just want to be sure it isn't heated. He told me, no, and that these stones are not heated locally at all.

I lost the sale, and ended up paying for a report that was wrong. It turns out that these Baringo stones were spewed out of a volcano long long ago, and were heated by nature on the way out. So labs may report them as heated. They certainly are not heated by man.

 

[Frost]

@Frost can you pls share the names of the two labs in Sri Lanka and which one in particular you trust?

The lab I was talking about above is GIC (Gemmological Institute of Colombo). Apart from having all the requisite equipment, I've outlined the other reasons for my thoughts in the post above yours.

I can knock on wood and say that we've had zero problems so far - which may or may not mirror other people's experiences, but I doubt we've been lucky time and again with what must be thousands of stones by now.

However, I'd also like to point out a caveat: some years ago, we saw some inconsistencies on one specific thing - vivid hot pink sapphires. We've seen some clashing results on "low heat vs. no heat" in that one particular color/variety category, possibly because they interpret heat tolerance differently for that one variety as opposed to some other labs like AGL (who called the stone a heated ruby, which it was not).

As many other labs will clearly state, the lines on that aren't always entirely clear (due to different geological conditions in different deposits and sometimes resultant difficulties in determining what was done by nature and what by human hands), but to be safe we still as a result of that now no longer believe any hot pink sold locally to be unheated - even the ones that are, since statistically some must be. So we no longer offer "unheated hot pink" as a gemstone category at all, which is a loss because there are some gorgeous stones out there.
But this has exactly zero bearing on high heat, diffusion etc. which was the subject of my initial post.

Other than that, we've submitted plenty of vivid blues, vivid yellows, padparadschas, orange sapphires etc. and have had no issues at all so far whenever the stones were re-tested.

But trade terms wise... honestly I’ve seen so many dubiously named gems even from VERY reputable labs that I think is still best to trust your own eye.

The only correct answer, exactly. Labs are ultimately never a replacement for experience and an experienced enough eye should absolutely override whatever the lab states. There's a ton of stones out there with both "trusted" and "untrusted" reports which are basically nonsense - plus trade terms evolve slowly, so the only way to keep up is to be educated and keep looking at a lot, lot, lot of stones all the time.

Another consideration is that labs often grade with various types of daylight calibrated artificial lights in order to remain consistent; and there are sapphires which look completely different under those vs. in actual diffused daylight outdoors. So daylight outdoors should take precedence over artificial light even if that means disagreement with a more favorable lab opinion, since daylight is more likely to mirror what most people (the potential buyers for that stone) will see in person once they receive it.

 

[Kevin Bryant]

As a seller I sell both, General I dont cert stones I cut unless they are above a certain value wholesale, sending a gemstone to GIA with shipping is a $100 plus affair we dont always make great margins on selling and we also have to hold gemstones for in some cases years before selling it so the cost can mount up. I am always open to send one to GIA are anyplace else at the customers request. But for me unless I am looking at a $5k plus gem its not going to GIA, but I also sell more wholesale then to the public so most of my customers are GIA grads are been in the businesses long enough to be able to check anything I sell. On diamonds its a different story, price on diamonds are set industry wide off of a monthly price sheet that comes out, knowing with out a dough how it grades allows you to know what to expect and how much you will get for it so almost every diamond I buy I cert. General when I send a diamond off to GIA with in 24 hours of returning its sold and out the door. Colored has no monthly price sheet so that is why certs are not worth as much on smaller gems on the colored stone side and general when color comes back from GIA it spends months in the safe before it sells.

 

[T L]

Another consideration is that labs often grade with various types of daylight calibrated artificial lights in order to remain consistent; and there are sapphires which look completely different under those vs. in actual diffused daylight outdoors. So daylight outdoors should take precedence over artificial light even if that means disagreement with a more favorable lab opinion, since daylight is more likely to mirror what most people (the potential buyers for that stone) will see in person once they receive it.

Some stones, like red spinels or rubies, have strong red fluorescence in daylight, but can be almost brownish in artificial light. Do you think those should be graded in natural light? Most stones are purchased indoors, so I don’t think that’s necessarily what they’ll see when they purchase it. Many on this forum can attest to that. They often receive stones that look nothing like the online vendor photos. This is often due to the vendor taking the UV photos and nothing else.

 

[kenny]

Would you consider purchasing one? If so, under what conditions?

No.
I don't gamble with my hard earned money.

 

[PrecisionGem]

Some stones, like red spinels or rubies, have strong red fluorescence in daylight, but can be almost brownish in artificial light. Do you think those should be graded in natural light? Most stones are purchased indoors, so I don’t think that’s necessarily what they’ll see when they purchase it. Many on this forum can attest to that. They often receive stones that look nothing like the online vendor photos. This is often due to the vendor taking the UV photos and nothing else.

I think one of culprits is the bulbs people have. Many people have those CFL bulbs, which are not close to a full spectrum, and most thing look pretty bad with them. Even wall color of paint.

I photograph my stones with SOLUX bulbs which are the bulbs most art galleries and museums use as they are a full spectrum and show true colors.

I see pictures posted on here that look nothing like the stone does in real life. I think these are a combination of the bulbs, and the images not being color balanced for the light source. Photographing gems is very challenging.

 

[Frost]

Some stones, like red spinels or rubies, have strong red fluorescence in daylight, but can be almost brownish in artificial light. Do you think those should be graded in natural light?

Technically yes, absolutely - diffused daylight is/has been the golden standard for quite a while (can be daylight indoors too, next to a window for example). It's much more accurate for blue sapphires, for example, since artificial lights (incandescent excluded) tend to make them look quite a bit nicer than daylight.

But in cases like you mentioned where you get that typical red with a bit of brown or a blackish undertone - like in so many different rubies, garnets, spinels - that should either be mentioned or represented in the images. Although to be fair, it would be pretty difficult to hide even if one takes only daylight images since there's still a pretty visible difference between stones that behave like that and those that don't (it's like the difference between a "conventional" red spinel and a Mahenge one - whichever light you take the photos in, the difference will be visible and the latter is likely to look good at all times while the former won't). Or in other words, what the gem trade calls "open" colors (persistently lit and saturated) and "closed" ones (ones that brown/black out).

They often receive stones that look nothing like the online vendor photos. This is often due to the vendor taking the UV photos and nothing else.

Did you mean artificial light (studio), rather than UV? Still - the simple solutions are:
1) the vendor should ensure that their images look true to the stone by whatever means necessary
2) take a range of photos, like studio, daylight etc. which most already seem to do

While the buyer on the other hand should ask for photos and/or videos in as many different lighting scenarios as they please in order to decide whether the stone is for them.

In a nutshell - within the trade worldwide, colored stones are judged in diffused daylight to ascertain the "base" color. Nothing wrong with that. But yes, by all means one should ask for different lighting scenarios if there's any worry about it since all of them shift color to one degree or another, it's simply a property of the material.