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advice on stone (especially IGI color grading)

rootpi

Rough_Rock
Joined
Apr 16, 2016
Messages
9
Hi all!

I am very interested in this diamond:
http://www.jamesallen.com/loose-diamonds/round-cut/2.43-carat-i-color-vs2-clarity-excellent-cut-sku-923297

The cut looks good (crown angle a bit higher than ideal, but otherwise all seems promising), and I think the price was reasonable though I'm not an expert. My only concern is that the certificate is IGI not GIA. I don't care if the clarity is "actually" SI1 instead of VS2, because it looks very clean to me in the magnified image (but let me know if any of you see anything differently). But I've read that they also are sometimes loose on the color - I would have preferred a G or H to begin with, but probably happy with an I for the right stone if it really is an I not a J/K (partly because the setting will be white gold).

On the other hand I have also read that IGI has been getting stricter recently and improving their reputation, and seems like James Allen wouldn't list anything too far off (right?). We can't judge the color online, but any thoughts from the community on how worried I should be about this, or whether an I is okay to begin with? I don't need it to be colorless or stand up to perfect scrutiny / comparison, just want it to look great faceup in the setting. Or any other thoughts / comments / input on this one before I make a final decision?

thanks much!
 

diamondseeker2006

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I would never buy a stone without a GIA or AGS report. You get what you pay for, so if the cost was lower than other comparable GIA stones, it just means that it is lower color and/or clarity than stated. I wouldn't even consider that stone without an idealscope image, because with that crown angle, it very possibly has some leakage.

I just looked for other options and so many of them had a crown angle over 36!

That stone gets a 3.7 on the HCA, which we normally would not recommend. Stones scoring 2 or under are best, and some in the low 2 range are also fine when confirmed by an idealscope or ASET image.

The stone you linked scored Very Good on Light Return, Fire, and Spread, and only Good on Scintillation. What we normally want to see is excellent for everything but spread which usually is very good in ideal cut stones.
 

MollyMalone

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Since it's a loose stone graded by IGI Mumbai, thought you might like to see these (positive) observations by PS Trade member John Pollard
https://www.pricescope.com/author/john-pollard
and some other Trade members in recent years:
[URL='https://www.pricescope.com/community/threads/buying-a-diamond-ring-in-dubai.212793/#post-3871158?hilit=Mumbai#p3871158']https://www.pricescope.com/community/threads/buying-a-diamond-ring-in-dubai.212793/#post-3871158?hilit=Mumbai#p3871158[/URL]

[URL='https://www.pricescope.com/community/threads/igi-grading-system.182725/']https://www.pricescope.com/community/threads/igi-grading-system.182725/[/URL]

[URL='https://www.pricescope.com/community/threads/igi-diamond-buying-advice.191543/#post-3488452']https://www.pricescope.com/community/threads/igi-diamond-buying-advice.191543/#post-3488452[/URL]

That said, the price is not showing on the JA page because the stone is "not available", which means no one here can venture an opinion on whether you could do better for the same price (or close to it), or what other compromises you might have to consider.

Have you asked JA for an ASET image? ETA: JA will give you ASETS on 3 of their stones, but think you can only make 1 request, so don't ask for an ASET on this one just yet.

Also, do you think you might ever want to upgrade the diamond? JA will credit 100% of the original purchase price of a loose stone toward a new stone -- provided the new stone is priced at at least 2x the price of the first stone (and if you have held onto the lab report). That's not bad, generally speaking (same as, e.g., Blue Nile), but there are vendors with even more favorable upgrade policies, although you can expect that their stones will be typically priced higher.
 

RockBrat

Shiny_Rock
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Feb 22, 2016
Messages
116
I like stones with larger crown angles and think the profile is very pretty. In the website video the stone looks like it could be pretty but I have no way of judging its light performance. I will say though it does not look like a true I color to me. My guess is it's a K colored diamond.
 

rootpi

Rough_Rock
Joined
Apr 16, 2016
Messages
9
Thank you all - I really appreciate the time and this is all quite helpful, even if headed in slightly different directions. It sounds like IGI Mumbai is decent on the whole, albeit possibly off by a grade. That's not great but at least makes me worry less about getting a dud. On the other hand there seems to be more concern about the crown angle and hence the associated HCA score. Possibly ASET can help there.

I didn't see a lot of options in this range, but of course I probably wasn't able to search as efficiently as many of you. My goal would be a 2.1-2.5 ct stone, G/H/I color, eye clean, the more perfect the cut the better of course. See any good options out there? There's no specific deadline so I can afford to wait, but it would also be nice to not spend too much (more) time on it!

merci
 

rootpi

Rough_Rock
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Apr 16, 2016
Messages
9
Sorry didn't answer your specific questions MollyMalone: I have not yet requested an ASET, so I agree it makes sense to wait and see if there are some others to ask about. I would prefer to go with JA because I want the same custom setting that I got from them in the past, but of course if there's a clearly better loose diamond elsewhere then that matters more.

We might want to upgrade in the future, though I doubt (?) it would be for more than twice the price of this one, which already feels like a lot! (just under $18k, if that helps making the comparisons)
 

ADN

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Messages
311
diamondseeker2006|1460836072|4020130 said:
I would never buy a stone without a GIA or AGS report. You get what you pay for, so if the cost was lower than other comparable GIA stones, it just means that it is lower color and/or clarity than stated.
Hi rootpi - I'm going to have to respectfully disagree with diamondseeker2006 (sorry :wavey: )

Based on colour / clarity / cut / symmetry / polish / fluorescence - - the difference between the GIA & IGI grading is virtually non-existent. IGI India/HK/Belgium are all pretty spot on with GIA for colour and SI1+ clarity goods...SI2s...hmmm...ok maybe you'd want to take a closer look (in my personal experience).
Here's a link to a small industry test that was conducted in 2013 (some could argue that there weren't any SI2s in the test, and that this may have resulted in more differences - - but overall they're pretty good.)
http://www.diamonds.net/News/NewsItem.aspx?ArticleID=43417
I think IGI tend to cop a bit of unfair criticism in the diamond forum world...and unfortunately, more often than not it's the end consumer that can miss out on some really nice stones because they've read/been told online to stay away from anything other than GIA or AGS.
Hope this helps
 

rootpi

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Apr 16, 2016
Messages
9
Thanks ADN (et al.) - I think I saw that report referenced elsewhere before but had forgotten about it, and it certainly does make me feel better about IGI and the color.

I guess that just leaves the cut question and the HCA score. I looked around a bit more on JA and found these two for about the same price, somewhat smaller, but with HCA scores in the mid 2 range:
http://www.jamesallen.com/loose-diamonds/round-cut/2.21-carat-i-color-si1-clarity-excellent-cut-sku-697117
http://www.jamesallen.com/loose-diamonds/round-cut/2.21-carat-i-color-vs1-clarity-excellent-cut-sku-859622
I don't really know how to judge that tradeoff, but it sounds like it might at least be worth trying to get the more precise views of several of these in order to compare.

To find something with HCA well under 2 I had to both go down in size and noticeably up in price:
http://www.jamesallen.com/loose-diamonds/round-cut/2.11-carat-i-color-vs2-clarity-excellent-cut-sku-1009156

Or finally still higher in price but close to the same size as the original, with HCA of 2.3:
http://www.jamesallen.com/loose-diamonds/round-cut/2.31-carat-i-color-vs2-clarity-excellent-cut-sku-936824
 

MollyMalone

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Rockdiamond

Ideal_Rock
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ADN|1460863907|4020269 said:
diamondseeker2006|1460836072|4020130 said:
I would never buy a stone without a GIA or AGS report. You get what you pay for, so if the cost was lower than other comparable GIA stones, it just means that it is lower color and/or clarity than stated.
Hi rootpi - I'm going to have to respectfully disagree with diamondseeker2006 (sorry :wavey: )

Based on colour / clarity / cut / symmetry / polish / fluorescence - - the difference between the GIA & IGI grading is virtually non-existent. IGI India/HK/Belgium are all pretty spot on with GIA for colour and SI1+ clarity goods...SI2s...hmmm...ok maybe you'd want to take a closer look (in my personal experience).
Here's a link to a small industry test that was conducted in 2013 (some could argue that there weren't any SI2s in the test, and that this may have resulted in more differences - - but overall they're pretty good.)
http://www.diamonds.net/News/NewsItem.aspx?ArticleID=43417
I think IGI tend to cop a bit of unfair criticism in the diamond forum world...and unfortunately, more often than not it's the end consumer that can miss out on some really nice stones because they've read/been told online to stay away from anything other than GIA or AGS.
Hope this helps
I'm going to respectfully disagree with ADN, and agree with diamondseeker on this.
It's not really about how good IGI is-it's the fact that IGI is simply not accepted by dealers on important stones.
We have purchased a few smaller stones that the cutter had already submitted to IGI- but on a 2ct?
I strongly suggest sticking with a GIA graded stone.
 

MollyMalone

Ideal_Rock
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Rockdiamond|1460911931|4020451 said:
I'm going to respectfully disagree with ADN, and agree with diamondseeker on this.
It's not really about how good IGI is-it's the fact that IGI is simply not accepted by dealers on important stones.
We have purchased a few smaller stones that the cutter had already submitted to IGI- but on a 2ct?
I strongly suggest sticking with a GIA graded stone.
As an "end consumer", not someone in the trade, I have a different take, Rd : I'm buying a stone, not the paper, so I would not flatly rule out IGI -- especially if I had no intention of selling it "as is" or trading it in (which is another reason I asked rootpi if he thought there might be an upgrade, instead of it being a forever ring).

And Wink's very recent comment, less than 2 weeks ago, about GIA's own, collective inconsistencies
GIA now has many labs around the world and they are having serious problems with consistency, so while the likelihood of them being two color grades off is low, it is possible.
[URL='https://www.pricescope.com/community/threads/color-tolerance.221996/#post-4016171?hilit=gia#p4016171']https://www.pricescope.com/community/threads/color-tolerance.221996/#post-4016171?hilit=gia#p4016171[/URL]
-- an observation I've seen elsewhere of late -- is less than comforting reassurance about GIA-graded stones.
 

Rockdiamond

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I totally get what you're saying Molly.
For me, it's more about the seller.
Nothing in life is 100%- but the overwhelming likelihood is that the seller understands the problems an IGI graded stone will face on the market. For that reason it's highly unlikely the cutter, or dealer would avoid GIA unless there's something to hide.
As I mentioned, on a $1000 diamond, the issue is far less crucial to the buyer.
As far as comfort with GIA- the important take away I got from what Wink said was that a two grade difference on a GIA report is extremely rare.
I disagree that there's serous problems with consistency on GIA reports.
We submit stones to GIA pretty much on a daily basis- my experience is that they are remarkably good at the difficult and subjective job of diamond grading.
 

rootpi

Rough_Rock
Joined
Apr 16, 2016
Messages
9
Yes in this case I'm purely an end consumer and want a great looking stone, not necessarily one with a high trade-in or sales value. I certainly hope the ring is forever! It sounds like a small risk with IGI and a very small risk with GIA, so I'd prefer the latter but think I can live with the former if everything else pointed in that direction. Note that the other stones I found above, with lower HCA scores, are all GIA so maybe that also slightly argues in their favor - but at a distinct tradeoff in terms of size (and/or price).

Thanks also for the input re HCA (and the link to John Pollard's nice analogy), which I understand better but not perfectly. It can't pick a perfect stone but it can potentially rule out ones that are unlikely to be wonderful. But since some folks set a cutoff of 2, wouldn't that suggest I do need to be looking below that level? Others seems to say 2.5 is the max, and of course my natural instinct is that there isn't some threshold but rather the lower the score the higher the probability, at least for anything at or above 2.

The HCA tool spits out 3.7 for my original choice and calls that "very good" - "worth buying if the price is right" (which it seems to be, given what else I've seen). I guess my question would be: if I find a 2.1 ct or 2.2 ct stone (likely at a somewhat higher price) with better visual characteristics (found via HCA but hypothetically let's say it gets confirmed via idealscope or whatever), is it going to look better / larger / more brilliant overall than a 2.4 ct stone with slightly less good (but hardly bad) visual characteristics? That seems to be the decision I may have to make. I care a little bit about the size per se but not much; in the end what matters is how it looks overall (and the price of course).
 

Rockdiamond

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For my money I'd look at a 3.7HCA GIA graded diamond before a lower ( better HCA) scoring IGI graded stone. But for me, there's less of an issue- I can grade the diamond myself.
I've seen plenty of amazing diamonds that scored well below 2 ( higher than 2) on HCA.
As a consumer you have no idea how far off IGI is on any given stone- that's an issue.
 

ADN

Shiny_Rock
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Rockdiamond|1460920299|4020511 said:
For my money I'd look at a 3.7HCA GIA graded diamond before a lower ( better HCA) scoring IGI graded stone. But for me, there's less of an issue- I can grade the diamond myself.
I've seen plenty of amazing diamonds that scored well below 2 ( higher than 2) on HCA.
As a consumer you have no idea how far off IGI is on any given stone- that's an issue.
Hey mate :wavey: - I don't want to jack the post by us going too far off the original topic - sorry rootpi :)

"It's not really about how good IGI is-it's the fact that IGI is simply not accepted by dealers on important stones."
The same could be said about AGL and would be just as applicable - - there are way more IGI than AGL in the trade - - just because something isn't accepted by dealers doesn't mean that it shouldn't be ;-)

All the same machines are used to take a diamonds measurements whether GIA/IGI/AGL/HRD/etc., so I don't think there is any real issue with this part of the grading/measuring system? And if we agree on that, then it seems (in your example bolded above) that your choice of selecting a GIA stone with a lower HCA score rather than an IGI with a better HCA score is based more on market perception/saleability rather than the diamond itself?
And that's fair enough (for those of us in the trade) - at the end of the day we supply a demand. I buy/sell way more GIA than IGI for the simple reason that GIA are what is in demand, whereas IGI (at least in the US/Aus markets) are not so much -- so why would we buy a stone with IGI knowing we'd have trouble moving it (for no other reason than market perception) when we can get the exact same stone with GIA and not have it sitting in the safe simply because of market supply/demand - - it'd be like me buying a whole bunch of princess cuts when everyone want rounds...not a great business decision...even though there is nothing wrong with the princess cuts.
And for what it's worth, I completely agree about there being lots of beautiful stones that don't do well on the HCA...I've never actually even considered the HCA score when buying for stock :D
And regarding "As a consumer you have no idea how far off IGI is on any given stone- that's an issue", the same can be said for any lab - I've seen some shockers come out of both camps, so I've never bought a stone of any real financial value straight off a piece of paper - like we've all said on many occasions, you buy the stone not the paper.
 

rootpi

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No worries ADN - I have found the whole discussion to be not just interesting itself but also very informative / helpful for my own decision, though of course it can't answer all the questions. I did request ideal scope images from JA for three of the most promising stones, including my original one (despite the slightly worse HCA) but unfortunately they are all out of the country so don't have IS images available. I will try to speak with a technical person there once they actually have the stone in hand, and hopefully that will yield enough info, because as you say it's the stone that matters! (not IGI vs GIA, better or worse HCA, etc)
 

Rockdiamond

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ADN|1460943154|4020625 said:
Rockdiamond|1460920299|4020511 said:
For my money I'd look at a 3.7HCA GIA graded diamond before a lower ( better HCA) scoring IGI graded stone. But for me, there's less of an issue- I can grade the diamond myself.
I've seen plenty of amazing diamonds that scored well below 2 ( higher than 2) on HCA.
As a consumer you have no idea how far off IGI is on any given stone- that's an issue.
Hey mate :wavey: - I don't want to jack the post by us going too far off the original topic - sorry rootpi :)

"It's not really about how good IGI is-it's the fact that IGI is simply not accepted by dealers on important stones."
The same could be said about AGL and would be just as applicable - - there are way more IGI than AGL in the trade - - just because something isn't accepted by dealers doesn't mean that it shouldn't be ;-)

All the same machines are used to take a diamonds measurements whether GIA/IGI/AGL/HRD/etc., so I don't think there is any real issue with this part of the grading/measuring system? And if we agree on that, then it seems (in your example bolded above) that your choice of selecting a GIA stone with a lower HCA score rather than an IGI with a better HCA score is based more on market perception/saleability rather than the diamond itself?
And that's fair enough (for those of us in the trade) - at the end of the day we supply a demand. I buy/sell way more GIA than IGI for the simple reason that GIA are what is in demand, whereas IGI (at least in the US/Aus markets) are not so much -- so why would we buy a stone with IGI knowing we'd have trouble moving it (for no other reason than market perception) when we can get the exact same stone with GIA and not have it sitting in the safe simply because of market supply/demand - - it'd be like me buying a whole bunch of princess cuts when everyone want rounds...not a great business decision...even though there is nothing wrong with the princess cuts.
And for what it's worth, I completely agree about there being lots of beautiful stones that don't do well on the HCA...I've never actually even considered the HCA score when buying for stock :D
And regarding "As a consumer you have no idea how far off IGI is on any given stone- that's an issue", the same can be said for any lab - I've seen some shockers come out of both camps, so I've never bought a stone of any real financial value straight off a piece of paper - like we've all said on many occasions, you buy the stone not the paper.
HI all!
ADN- GIA is the standard by which the other labs are judged. GIA can make an error- and of course they have- but it's very rare that they do. IN general, dealers/cutters submitting to GIA are interested in accurate grades, so if there is a clear error, the dealer/cutter will catch it and correct it. Bottom line is that you can't find a lot of misgraded GIA stones on the market. "Shockers" are associated with EGL especially. Regardless, GIA's track record and industry standing as the leader are not in question.
You mentioned AGL- I assume you mean AGSL.
I agree that IGI grades more stones than AGSL_ but not for dealer to dealer trading. AGSL trades at parity with GIA dealer to dealer.

Dealer behavior is like the "canary in the coal mine" for consumers. It matters a lot that a 2ct IGI graded stone will trade for a large percentage less than a GIA graded stone of the same color/clarity.
This is based on dealer behavior. Cutters and dealers know trade diamonds for a living, so watching that aspect of diamond buying is very important for consumers.
This does filter down to the consumer level, as you point out. Again, all for good reason, and I can see no reason for a consumer to try and buck that trend other than trying to "game the system". If a seller can convince a consumer that IGI has market parity to GIA they can increase profits, and the consumer gets less for their money.
As you point out, a 3.7HCA score will not affect trading price- but of course lack of GIA report will.

rootpi- thanks for being an "inquiring mind"!
Neither ADN or I can comment on any stone from another seller- but the general rules will apply:)
 

John Pollard

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Rockdiamond|1460918788|4020504 said:
Nothing in life is 100%- but the overwhelming likelihood is that the seller understands the problems an IGI graded stone will face on the market. For that reason it's highly unlikely the cutter, or dealer would avoid GIA unless there's something to hide.
With respect David, I know this remains the sermon 'round old-school USA water coolers and fax machines (haha). But globalization has created other legitimate options. Not nearly as big, but legit.

One example: Just as AGSL's proposition is suited to a certain market-segment here, there's market demand for 'Hearts & Arrows' assessment in Asia-Pacific markets. GIA does not offer it. IGI and HRD do. They also have faster different turnaround times. IGI also has schools of gemology in HK and Shanghai, training and building loyalty among professionals in China just like GIA did in the USA 'back in the day.'

As for standards: In China, specifically, grading is policed by the National Gemstone Testing Center (NGTC). If you have a store carrying diamonds with foreign grading reports (GIA, IGI, HRD, AGSL, etc.) the NGTC visits and takes some of them for testing. If any are judged to be overgraded the goods are frozen, the store is fined and they must secure a fresh report from the NGTC for those diamonds. In this policing system high strictness = more fines. So color and clarity grading enjoy rather even footing among the labs serving the Asia-Pacific. It’s why EGL could not penetrate that market.

Yet another practice in China is securing two different lab reports for the same diamond. This started because Chinese consumers sought western documentation over national reports. This has grown in practice, also due to the paragraph above. When you see the frequency and uniformity of those results it dispels the idea that using another lab suggests "something to hide."

GIA is still the world authority. If you wanted to sell an auctionable diamond, in any market, that’s a no-brainer. GIA also has the most market share, by far, for good reason. But other laboratories can and do operate successfully. Like AGSL they don't threaten GIA, they complement GIA.
 

wildcat03

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rootpi|1460866839|4020296 said:
Thanks ADN (et al.) - I think I saw that report referenced elsewhere before but had forgotten about it, and it certainly does make me feel better about IGI and the color.

I guess that just leaves the cut question and the HCA score. I looked around a bit more on JA and found these two for about the same price, somewhat smaller, but with HCA scores in the mid 2 range:
http://www.jamesallen.com/loose-diamonds/round-cut/2.21-carat-i-color-si1-clarity-excellent-cut-sku-697117
http://www.jamesallen.com/loose-diamonds/round-cut/2.21-carat-i-color-vs1-clarity-excellent-cut-sku-859622
I don't really know how to judge that tradeoff, but it sounds like it might at least be worth trying to get the more precise views of several of these in order to compare.

To find something with HCA well under 2 I had to both go down in size and noticeably up in price:
http://www.jamesallen.com/loose-diamonds/round-cut/2.11-carat-i-color-vs2-clarity-excellent-cut-sku-1009156

Or finally still higher in price but close to the same size as the original, with HCA of 2.3:
http://www.jamesallen.com/loose-diamonds/round-cut/2.31-carat-i-color-vs2-clarity-excellent-cut-sku-936824
Of these, the only one I would consider would be the 2.11 ct I/VS2. The first option appears somewhat hazy to me - I think it's the twinning wisps and clouds. The stone is also deep and doesn't face up at what it should. The second option (2.21 I/VS1) is even deeper and faces up even smaller than the first.

The third is one worth getting an ASET/Idealscope on if they can. The table is a little big (59) for what I like and what people on here advise (54-57) but otherwise it looks nice. Notice that even though it is smaller in weight, it faces up just a bit smaller than the first two.

The fourth is ok. The crown is a little high and it is just a tad deep - making it face up a little small for its weight. I would pass on this one, too.
 

Rockdiamond

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John Pollard|1461000238|4020827 said:
Rockdiamond|1460918788|4020504 said:
Nothing in life is 100%- but the overwhelming likelihood is that the seller understands the problems an IGI graded stone will face on the market. For that reason it's highly unlikely the cutter, or dealer would avoid GIA unless there's something to hide.
With respect David, I know this remains the sermon 'round old-school USA water coolers and fax machines (haha). But globalization has created other legitimate options. Not nearly as big, but legit.

One example: Just as AGSL's proposition is suited to a certain market-segment here, there's market demand for 'Hearts & Arrows' assessment in Asia-Pacific markets. GIA does not offer it. IGI and HRD do. They also have faster different turnaround times. IGI also has schools of gemology in HK and Shanghai, training and building loyalty among professionals in China just like GIA did in the USA 'back in the day.'

As for standards: In China, specifically, grading is policed by the National Gemstone Testing Center (NGTC). If you have a store carrying diamonds with foreign grading reports (GIA, IGI, HRD, AGSL, etc.) the NGTC visits and takes some of them for testing. If any are judged to be overgraded the goods are frozen, the store is fined and they must secure a fresh report from the NGTC for those diamonds. In this policing system high strictness = more fines. So color and clarity grading enjoy rather even footing among the labs serving the Asia-Pacific. It’s why EGL could not penetrate that market.

Yet another practice in China is securing two different lab reports for the same diamond. This started because Chinese consumers sought western documentation over national reports. This has grown in practice, also due to the paragraph above. When you see the frequency and uniformity of those results it dispels the idea that using another lab suggests "something to hide."

GIA is still the world authority. If you wanted to sell an auctionable diamond, in any market, that’s a no-brainer. GIA also has the most market share, by far, for good reason. But other laboratories can and do operate successfully. Like AGSL they don't threaten GIA, they complement GIA.
Cool info John- however for clients and dealers in the US, Austrlaia, Canada, England- basically all the other countries besides China, any 2ct diamond without GIA or AGSL is hobbled. You can sell it, but not based on the Rap sheet, unless you downgrade by at least a few grades- In other words, a seller with a stone graded non GIA/AGSL as G color will trade like a J, or worse. I agree this is not fair, as IGI is churning out good reports on the whole, and is definitely well thought of with relation to EGL- but that has not had a market effect that I can see here in the states
But my comments are specifically for the English speaking market in the US, Aus/NZ/ Canada UK etc....
 

rootpi

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wildcat03|1461005694|4020852 said:
Of these, the only one I would consider would be the 2.11 ct I/VS2. The first option appears somewhat hazy to me - I think it's the twinning wisps and clouds. The stone is also deep and doesn't face up at what it should. The second option (2.21 I/VS1) is even deeper and faces up even smaller than the first.

The third is one worth getting an ASET/Idealscope on if they can. The table is a little big (59) for what I like and what people on here advise (54-57) but otherwise it looks nice. Notice that even though it is smaller in weight, it faces up just a bit smaller than the first two.

The fourth is ok. The crown is a little high and it is just a tad deep - making it face up a little small for its weight. I would pass on this one, too.
Awesome - thanks for the specific thoughts wildcat (and others, although I know the dealers can't get into details). Interestingly I had already essentially ruled out #2 and #4 myself. I hadn't noticed the haze on #1 (was looking too closely at the numbers, probably) but now that you mention it I certainly see it too. Presumably not just a trick of the light / photography?

But that still leaves #3 (the 2.11ct that scores under 2 on HCA) versus my original option (2.43ct scoring between 3 and 4). Unfortunately both diamonds are outside the country so they said they can't do IdealScope images as usual. So none of us can really tell which is cut better, and anything we say now is probabilistic in nature - I can live with that.

My question (and this is a hypothetical since we don't know about these stones, so the trade folks should feel free to weigh in!): if one diamond is very well cut but not perfectly cut, and it has a surface area about 8% larger than a smaller but extremely well cut stone, will it be as brilliant overall? That is, roughly speaking, even if the quality per carat is slightly lower, at what point does more carats still deliver the goods?
 

rootpi

Rough_Rock
Joined
Apr 16, 2016
Messages
9
Rockdiamond|1461008298|4020870 said:
Cool info John- however for clients and dealers in the US, Austrlaia, Canada, England- basically all the other countries besides China, any 2ct diamond without GIA or AGSL is hobbled. You can sell it, but not based on the Rap sheet, unless you downgrade by at least a few grades- In other words, a seller with a stone graded non GIA/AGSL as G color will trade like a J, or worse. I agree this is not fair, as IGI is churning out good reports on the whole, and is definitely well thought of with relation to EGL- but that has not had a market effect that I can see here in the states
But my comments are specifically for the English speaking market in the US, Aus/NZ/ Canada UK etc....
Now you're actually making me feel good about the IGI option: if they are generally solid reports but are undervalued because most of the market doesn't like them, and if all I care about is a beautiful stone, then it sounds like I might be getting a good deal by going with IGI in the anglo market...
 

rootpi

Rough_Rock
Joined
Apr 16, 2016
Messages
9
Rockdiamond|1460994105|4020801 said:
rootpi- thanks for being an "inquiring mind"!
You're welcome! I'm a social science researcher (economist to be precise) in my day job, so although diamonds are new to me this type of discourse makes me feel at home :)
 

Rockdiamond

Ideal_Rock
Trade
Joined
Jan 7, 2009
Messages
8,173
The important takeaway for the IGI option is that it should be substantially less expensive than a diamond having the same grade issued by GIA.
On that basis, and given that you'll be getting a money back guarantee, I'm sure you'll do fine.
 

Karl_K

Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
9,463
Something to keep in mind there are different igi labs and different igi reports.
The most common igi report in the US is is the valuation type report with the highly inflated value on it from the US lab, they are often graded set and should be avoided.
Sir John has somewhat convinced me that IGI labs outside the US are not all that bad.
Some links:
http://jcrs.com/newsletters/2006/2006_09.htm

http://jcrs.com/newsletters/2016/2016_01.htm
 
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