Can GIA tell definitively whether a D-Z diamond is natural or lab-grown? If so, how?

[kenny]

The title says it all.

I read how natural and LG diamonds have the exact same properties.
Sorry, I can't ignore the elephant in this room that begs the question.
I'm wondering whether GIA can tell LG from earth-mined.

Of course if GIA can't, that would have to remain a huge dark secret which must (like the recipe for Coke) be as closely guarded as the nuclear launch codes.
... because if revealed ... well, let's just not go there.

So if GIA can tell ... what IS the difference, and exactly how does GIA tell the difference? ... in layman's terms of course, if that's even possible.

And does the ID method require very advanced knowledge and costly instruments that less well-endowed labs would not have, much as what GIA uses needed to identify which green FCDs got their green from natural radiation in the earth over millions of years vs. radiation in a lab.

Legit and honest question since we natural lovers are still expected to pay natural prices.
I'm sure I'm not the only one wondering.

I'm sorry that this is (to say the least) an awkward question here ... and one that won't make me any friends.
But an inquisitive poster gotta ask what an inquisitive poster's gotta ask.

 

[Bron357]

Apparently the differences can be detected due to their different growth morphology.
Natural diamonds grow in 8 planes, HPHT diamonds grow in 14 planes and CVD diamonds grow in 1 plane. So in the raw state their shapes are completely difference. Once facetted those different planes disappear from visual appreciation but the fundamental differences in growth habit can still be identified with specialised equipment.
So GIA has developed a spectroscopy device that can distinguish between fluorescence patterns and “other factors” ( I presume that the other factors is proprietary information GIA wants to keep under their hat).
So, no, the ordinary person or even a qualified gemologist will have difficulty distinguishing natural from lab (in absence of other tell tail signs like graining) without specialised training and equipment.

 

[kenny]

Thanks Bron357.
Does this difference have any effect on index of refraction, or light performance?

IOW, if a LG is cut to the exact same dimensions as a natural would they have identical light performance?
Does anyone know of a video of two identically-cut diamonds, one natural and the other LG, side by side comparing light performance?

 

[Bron357]

It’s a bit scary when you think about it. Unless the lab diamond manufacturer inscribes the girdle and is up front about it, how can the average consumer tell if their diamond is natural or lab?
I was browsing a website and a 3 carat natural was close to $50,000, the comparable lab was a mere $4,000.
Most antique/ vintage/ pre loved diamond rings come without a lab report. Here in Australia we don’t even have a GIA office so how would we ever know if the $50,000 diamond we thought we bought wasn’t actually the $4,000 type?
And can we trust GIA 100%? Might they mistakenly, on Occassion, certify a lab as natural or vice versa? When there is a $46,000 price difference it does matter. Who is the “other” trusted source with better or different equipment and assessment criteria who can verify that GIA was correct or was incorrect?
Suddenly less than perfect diamonds with their natural millions of years process imperfections become a safer bet and because of that perhaps even more valuable.

 

[Slickk]

Hi @kenny I do not know what machine my jeweler used (sitting on his counter) but he was able to test my lab diamond and tell me that it was lab grown and even what method was used to produce it (CVD/HPHT). So I assume (I know, I know) that machine would be able to determine if a stone was earth mined.

 

[freddyboston]

i use one of these to test mine.....

 

[RunningwithScissors]

I'm absolutely not an expert, but I've read the same thing that Bron mentioned, that the growth patterns of natural and lab are different. Also I've read that some lab diamonds have metal inclusions from the "seeds" they were grown from, which makes some of them attracted to a magnet. Can an expert chime in and tell us if that is correct?

 

[nala]

Pawn shops have machines. If they are lab, they light up red. Here’s the thing, I saw one a year ago. I wonder how much technology has improved lgd’s or will improve them until there is no difference. Hope GIA is keeping up with lgd growers.

 

[glitterata]

You'd never mistake my natural diamonds for lab. They're either antiques, with bruted girdles and naturals leftover on the girdle (that name says it all), or brightly fluorescent I1s, with internal inclusions like crystals. I guess I'm lucky that I preferred flawed oddballs, now the market is full of lab D IFs.

 

[hiratop]

You'd never mistake my natural diamonds for lab. They're either antiques, with bruted girdles and naturals leftover on the girdle (that name says it all), or brightly fluorescent I1s, with internal inclusions like crystals. I guess I'm lucky that I preferred flawed oddballs, now the market is full of lab D IFs.

D Ifs are a small minority of LDGs.

 

[Tonks]

I have actually wondered about this and what effect it will have in valuation of fluorescence in mined diamonds. Historically fluorescence is a characteristic that will drive market price down. However, my understanding is that lab stones don’t have fluorescence (please someone correct me if I’m wrong). That would seem to make fluorescence a very easy (and low cost) way to test a stone to see if it’s earth mined.

Of course, that only works if your stone has it.

 

[glitterata]

D Ifs are a small minority of LDGs.

True, but they're pretty easy to find if you want them, and incredibly cheap compared to natural D IFs.

edited to add: I should have said "high color, high clarity" instead of D IF.

 

[nala]

I have actually wondered about this and what effect it will have in valuation of fluorescence in mined diamonds. Historically fluorescence is a characteristic that will drive market price down. However, my understanding is that lab stones don’t have fluorescence (please someone correct me if I’m wrong). That would seem to make fluorescence a very easy (and low cost) way to test a stone to see if it’s earth mined.

Of course, that only works if your stone has it.

This used to be the case. I don’t know if lgd has fluorescence now.

 

[freddyboston]

LGD do but it manifests differently vs Natural Blues - see @ 12 minutes

Facts, Fiction, and FAQs – Exploring Nuances of Lab Grown vs. Natural Diamonds

www.gcalusa.com

 

[lovedogs]

This used to be the case. I don’t know if lgd has fluorescence now.

Omg if lgd's could have the overblue of mined I would be so happy haha.

 

[nala]

Omg if lgd's could have the overblue of mined I would be so happy haha.

Give it time. Give it time. Lgd’s are a product of technology, after all.

 

[freddyboston]

Give it time. Give it time. Lgd’s are a product of technology, after all.

They might be able to create N3 centres which cause the Fluorescence if they cook the LGD in the Diamond Oven for a couple billion years

 

[Texas Leaguer]

GIA has been following the synthetic diamond process closely since the feat was first achieved in the 1950's. There is probably no bigger priority at GIA than maintaining the ability to seperate natural from lab grown diamonds, and they have plenty of resources to apply to the task. None of the other top tier laboratories report having any difficulty with identification either.

At the research level, the equipment is highly advanced and expensive. However, GIA has developed instruments based on that research that are more affordable and are now deployed throughout the industry.

While lab grown diamonds have essentially the same properties as natural diamonds, they are not EXACTLY the same as those that were formed 25 or more miles beneath the crust of the earth and brought to the surface by violent volcanic events. @Bron357 mentioned the differences in morphology.

If you are buying through legitimate sources, you have very little to be concerned about. However, lab diamonds do provide crooks with a tantalizing opportunity to defraud people who might not do a little due dilligence. A good piece of time honored advice that is even more relevant today is to choose your vendor first, then choose your diamond!

 

[Texas Leaguer]

Thanks Bron357.
Does this difference have any effect on index of refraction, or light performance?

IOW, if a LG is cut to the exact same dimensions as a natural would they have identical light performance?

The optical properties are essentially the same and therefore light performance should be the same, if all cutting aspects are equal. That said, some lab diamonds have transparency issues, especially CVD, which would diminish light performance.

Because CVD grown diamonds are not rigidly contained by enormous pressure on all sides during the process, and because they are sometimes subject to fluctuations in the growth chambe due to starting and stopping of the process, they tend to develop strain and/or striation in the carbon lattice that can result in slight haziness.

It should be noted that natural diamonds also can have compromised transparency due mainly to certain types of inclusions. Unfortunately, transparency is not something any of the gem laboratories measure or grade directly.

 

[kenny]

GIA has been following the synthetic diamond process closely since the feat was first achieved in the 1950's. There is probably no bigger priority at GIA than maintaining the ability to seperate natural from lab grown diamonds, and they have plenty of resources to apply to the task. None of the other top tier laboratories report having any difficulty with identification either.

At the research level, the equipment is highly advanced and expensive. However, GIA has developed instruments based on that research that are more affordable and are now deployed throughout the industry.

While lab grown diamonds have essentially the same properties as natural diamonds, they are not EXACTLY the same as those that were formed 25 or more miles beneath the crust of the earth and brought to the surface by violent volcanic events. @Bron357 mentioned the differences in morphology.

If you are buying through legitimate sources, you have very little to be concerned about. However, lab diamonds do provide crooks with a tantalizing opportunity to defraud people who might not do a little due dilligence. A good piece of time honored advice that is even more relevant today is to choose your vendor first, then choose your diamond!

Thanks @Texas Leaguer
This was very important and assuring for me to hear, especially from you.
I was hoping to hear from you on this, but didn't want to put you on the spot.

She went GAGA over my ACA, but wants a lab-grown.
After your post I'm sending her to WF, but told her to not mention my name.

Though she went GAGA, she is not THE Lady Gaga.

Which reminds me of that old Rodney Dangerfield joke.
"... That's no lady; That's my wife".

Hahahaha!

 

[oldminer]

There are a few things that anyone can know and remember to start their knowledge of how to identify Lab from Mined diamonds. The main concern for the general public are diamonds from D to J color. That's where the majority of money is spent by consumers for gem diamonds.

Lab diamonds of that range of color are 100% type IIa. Mined diamonds of that IIa type are close to 2% IIa types and 98% Type Ia diamonds. Being simply able to identify the IIa diamonds will allow a gemologist to pull all the lab diamonds out along with an occasional mined one. Right away, only a good solution for beginning identification. You need a tool that detects Short Wave UV transparency. You can test for that in a few seconds with the right equipment. Not necessarily inexpensive equipment, but not multi-thousands of dollars, either.

Secondly, no Lab diamond fluoresces blue to Long Wave UV at all from D to J range. Most Lab diamonds don't fluoresce any color under Long Wave UV. Any diamond that is put under a 365/395nm long wave UV-A lamp that fluoresces blue, is a Mined diamond. Simple and helpful ID. Anyone can do this.

Invest in a Short Wave UV lamp 225 to 265nm, the shorter wavelength the better and the stronger lighting the better. Wear protective glasses and gloves. Nearly all Lab diamond fluoresce to SWUV aqua to teal colors and some will phosphoresce after the light is turned off. Nearly no Mined diamonds will do this. Stronger SW fluorescence than LW fluorescence is a big clue to Lab grown, too. These separations are simple to handle, but many jewelers and consumers just don't think it is possible. Most of the separations are not high tech.

Looking at every important stone to see if it happens to be laser inscribed LG or LGD, or has a document number that can be looked up is very helpful and often is found easily on the stone. Not all are marked, but many are. We like honesty.

There are visual tests done inside crossed Polaroid plates that display any strain inside diamonds. Diamonds from HPHT often show no strain, mined diamonds generally have strain of certain types, and CVD grown diamonds have layered strain typical of they way they are grown. This is not 100% accurate, but it isn't rocket science, either. This information is given in classes, webinars and in books with lots of photos. If you want to know, the answers, are all out there.

Major labs have a huge investment in complex tools to further identify colored diamonds and diamonds below the J range. All of these tools are for sale and many smaller labs have made large investments to further their study and marketing. My big problem is that the technology of making diamonds today may change over time making costly machines into large door stops. We'll need to depend on major labs for the complex work, but many parts of the process can be readily done if you study up and invest a bit of time and buy a few simple devices.

For the most part, most qualified gemologists and properly trained appraisers can separate Lab from Mined. They should be able to determine when they are not sure about an outcome, too. That's when a major lab gets involved.

Lab diamonds are highly similar to Mined diamonds, but they are not identical in all respects. I would think they never will be made identically since no business can plant a diamond seed and wait a few million years for the seed to germinate. Making things rapidly and at a reasonable cost is what we are learning to do. Lab diamonds look great and the price is getting lower and lower.

What an interesting time to see innovation compete with a very mature traditional market. Everything will settle out and we 'll get back to a new normal. A free market economy is best in the long term. Rarity has its place and so does mass production. Choice is in the hands of consumers.

 

[Texas Leaguer]

There are a few things that anyone can know and remember to start their knowledge of how to identify Lab from Mined diamonds. The main concern for the general public are diamonds from D to J color. That's where the majority of money is spent by consumers for gem diamonds.

Lab diamonds of that range of color are 100% type IIa. Mined diamonds of that IIa type are close to 2% IIa types and 98% Type Ia diamonds. Being simply able to identify the IIa diamonds will allow a gemologist to pull all the lab diamonds out along with an occasional mined one. Right away, only a good solution for beginning identification. You need a tool that detects Short Wave UV transparency. You can test for that in a few seconds with the right equipment. Not necessarily inexpensive equipment, but not multi-thousands of dollars, either.

Secondly, no Lab diamond fluoresces blue to Long Wave UV at all from D to J range. Most Lab diamonds don't fluoresce any color under Long Wave UV. Any diamond that is put under a 365/395nm long wave UV-A lamp that fluoresces blue, is a Mined diamond. Simple and helpful ID. Anyone can do this.

Invest in a Short Wave UV lamp 225 to 265nm, the shorter wavelength the better and the stronger lighting the better. Wear protective glasses and gloves. Nearly all Lab diamond fluoresce to SWUV aqua to teal colors and some will phosphoresce after the light is turned off. Nearly no Mined diamonds will do this. Stronger SW fluorescence than LW fluorescence is a big clue to Lab grown, too. These separations are simple to handle, but many jewelers and consumers just don't think it is possible. Most of the separations are not high tech.

Looking at every important stone to see if it happens to be laser inscribed LG or LGD, or has a document number that can be looked up is very helpful and often is found easily on the stone. Not all are marked, but many are. We like honesty.

There are visual tests done inside crossed Polaroid plates that display any strain inside diamonds. Diamonds from HPHT often show no strain, mined diamonds generally have strain of certain types, and CVD grown diamonds have layered strain typical of they way they are grown. This is not 100% accurate, but it isn't rocket science, either. This information is given in classes, webinars and in books with lots of photos. If you want to know, the answers, are all out there.

Major labs have a huge investment in complex tools to further identify colored diamonds and diamonds below the J range. All of these tools are for sale and many smaller labs have made large investments to further their study and marketing. My big problem is that the technology of making diamonds today may change over time making costly machines into large door stops. We'll need to depend on major labs for the complex work, but many parts of the process can be readily done if you study up and invest a bit of time and buy a few simple devices.

For the most part, most qualified gemologists and properly trained appraisers can separate Lab from Mined. They should be able to determine when they are not sure about an outcome, too. That's when a major lab gets involved.

Lab diamonds are highly similar to Mined diamonds, but they are not identical in all respects. I would think they never will be made identically since no business can plant a diamond seed and wait a few million years for the seed to germinate. Making things rapidly and at a reasonable cost is what we are learning to do. Lab diamonds look great and the price is getting lower and lower.

What an interesting time to see innovation compete with a very mature traditional market. Everything will settle out and we 'll get back to a new normal. A free market economy is best in the long term. Rarity has its place and so does mass production. Choice is in the hands of consumers.

This is the kind of post that makes Pricescope a great forum and a great community!