AGS vs GIA

[hearts-arrows_girl]

I currently own a 2.19 Stone AGS000. I have been considering getting a slightly larger stone (2.60-2.95), but I can only find GIAXXX in my search criteria. The question is, in my search I found there are very few AGS stones in the brick & mortar and virtual market. If AGS is the top cut stone, does that mean that most stones graded GIA XXX would not get the top grade from AGS? Since AGS stones command a higher price, wouldn’t a vendor want to make extra money by sending it to AGS to be graded AGS000? (I am locked into a brick & mortar location for my upgrade, so I have to go through their diamond vendor. Since my current stone from them was also listed in the virtual stones on Pricescope, I know it is possible to get some virtual stones, so I’ve been doing a search here also).
I’m not looking for help finding a stone, I’m just trying to figure out the AGS vs GIA thing, I have found a few candidates that are graded by GIA, but I’m worried they won’t have the sheer perfection of my AGS000 stone.

 

[CareBear]

The question is, in my search I found there are very few AGS stones in the brick & mortar and virtual market. If AGS is the top cut stone, does that mean that most stones graded GIA XXX would not get the top grade from AGS? Since AGS stones command a higher price, wouldn’t a vendor want to make extra money by sending it to AGS to be graded AGS000?

Yep! Most GIA ex/ex/ex would not get the top grade from AGS. At the same time, that might not be the reason for not sending the stone to AGS. Most consumers have never heard of AGS and everyone knows and trusts GIA.

 

[crbl999]

I’m not looking for help finding a stone, I’m just trying to figure out the AGS vs GIA thing, I have found a few candidates that are graded by GIA, but I’m worried they won’t have the sheer perfection of my AGS000 stone.

Yes, not all GIA EX/EX/EX stones are well cut. These specs should get you close to an ideal cut grade:

54-57 table
60-62.4 depth
34-35 crown
40.6-40.9 pavilion
75-80 LGF

If you would like some feedback on any stones that you are considering, post the specs and we will be glad to help.

 

[TreeScientist]

Yep! Most GIA ex/ex/ex would not get the top grade from AGS. At the same time, that might not be the reason for not sending the stone to AGS. Most consumers have never heard of AGS and everyone knows and trusts GIA.

Exactly. Not every GIA XXX is well cut, but there are still plenty of GIA XXX's that would get AGS 000 had they been sent to AGS. There are many reasons why a stone may be sent to one lab over the other beyond the cut, with the intended market for the stone being perhaps the largest factor. As @CareBear said, AGS is now well respected in America, but they are still practically unheard of throughout the rest of the world. GIA diamonds are still in the highest demand on the global market, so a large portion of the high quality polished diamonds will still go through GIA. Plus, GIA has multiple locations throughout the world, so it's often logistically easier to have diamonds graded at a lab close to where they were cut.

So, to answer your question, the grading report does not make the diamond. It's just a piece of paper that gives you information that you can use to judge the diamond. A GIA XXX can still possess the "sheer perfection" that you're talking about. Just take a look at JannPaul (search them on YouTube), a SuperIdeal vendor in Singapore that mainly carries GIA-graded diamonds, because GIA is still the most trusted lab in the eyes of most SE Asians.

Judge a diamond by the quality of its cut (which can be determined from the geometry and ASET/H&A/IS images) not by the grading lab or the brand slapped on the stone.

 

[diamondseeker2006]

Yes, there are definitely GIA XXX stones that would get AGS 000. In fact, I have owned two modern round brilliants that were first graded by GIA and later sent to AGS when I sold them since I knew many people here prefer AGS. Both were graded AGS 000. One was a true hearts and arrows stone that Jon had sold me, so I knew it would get AGS ideal cut from the images he provided. The other was a stone I bought thinking I would make a three stone ring or maybe a pendant, but I eventually sold it instead.

So basically, you can find great stones that are GIA graded. It helps tremendously to have ASET images. I'd buy one and learn how to use it if your jeweler does not provide the images.

 

[hearts-arrows_girl]

Thank you all for your replies!
Carebear thanks for your response.
crbls999 I am familiar with those set of parameters and the HCA, thanks for posting them. Diamondseeker, yes, I will have to get an ASET thingy. I loved that you had a GIA stone, I have followed you for years and respect your expertise and advice. I will definitely consider a GIA stone. I had one before this one, but it wasn't as crisp.
TreeScientist-good points.

I think I have the answer to my question. Thank you all for your time!

 

[Dancing Fire]

IMO, both lab are equal, so don't mind buying either lab if I get enough information on the stone.

 

[Lovesparklesparle]

Is it preferable for an old cut to be graded by one lab or the other? If so why? Is one looked upon more favourably for antique stones?

 

[sledge]

Agree with sentiment that some GIA XXX stones could be regraded as AGS000 stones. Keep in mind AGS determines cut based on a 3D scan and model of the specific stone in question. The proportions reported by AGS are more accurate and trustworthy.

GIA does not use advanced 3D modeling and values are averaged and then rounded up or down. So while proportions get you close, it's my opinion you need advanced imaging to confirm expected light performance and symmetry.

If AGS000 is important to you, have you considered striking a deal with your jeweler that would conclude you being picky with GIA, making sure it passes advanced imaging tests and then sending to AGS for regrading? If it passes, you pay for the regrade but if not they do. This helps them put skin in the game and get you a quality stone as they have something to lose.

 

[WinkHPD]

IMO, both lab are equal, so don't mind buying either lab if I get enough information on the stone.

DF, I agree that both labs are attempting to be equal as far as color and clarity, and the only reason I say attempting is that with many laboratories around the world, GIA has a much more difficult time with consistency that AGS which has only one laboratory.

For cutting, I clearly like AGS much better.

Wink

 

[sledge]

DF, I agree that both labs are attempting to be equal as far as color and clarity, and the only reason I say attempting is that with many laboratories around the world, GIA has a much more difficult time with consistency that AGS which has only one laboratory.

For cutting, I clearly like AGS much better.

Wink

Great point about multiple locations causing issues with consistency. That is a real struggle regardless of specific industry or company.

Also, I would agree that AGS is much better for cutting. The averaging & rounding GIA does makes it feel like more like an estimate IMO.

 

[hearts-arrows_girl]

Good points Wink and Sledge. I’m not in a hurry to buy, so I think I’m going to hold out for an AGS stone that will take the guesswork out of picking a beauty, since the company I have to buy through does not do any of the usual testing they do here such as ASET, and I’m not really good at using those tools myself yet.

 

[JustinL]

Recently I have bought 3 diamonds (for my 3 stone ring) from 3 different vendor with the specs as below:
1) 0.3ct-F-VVS2-GIA XXX -> HCA 4.5 (when I buy, I didn't use the HCA tools and know nuts about the proportions)
2) 0.5ct-F-VS1-GIA XXX -> HCA 1.0
3) 0.3ct-F-SI1-AGS 000 -> HCA 1.5

I have received item 1 and 2 and they looks great. So, in my opinion, at the end of the day, both AGS and GIA are great! But, if you are looking for ideal cut, AGS will be useful unless you have all the time to scan through all the proportions % in all the websites for GIA graded stones (this is what I did for my diamond no 2 ).

 

[sledge]

Recently I have bought 3 diamonds (for my 3 stone ring) from 3 different vendor with the specs as below:
1) 0.3ct-F-VVS2-GIA XXX -> HCA 4.5 (when I buy, I didn't use the HCA tools and know nuts about the proportions)
2) 0.5ct-F-VS1-GIA XXX -> HCA 1.0
3) 0.3ct-F-SI1-AGS 000 -> HCA 1.5

I have received item 1 and 2 and they looks great. So, in my opinion, at the end of the day, both AGS and GIA are great! But, if you are looking for ideal cut, AGS will be useful unless you have all the time to scan through all the proportions % in all the websites for GIA graded stones (this is what I did for my diamond no 2 ).

I'm a little confused. Are you saying the 0.3ct stone with a 4.5 HCA (stone 1) looked as good as the 0.50ct stone with 1.5 HCA (stone 2)?

Also, if I'm reading correctly, you only received stones 1 & 2, and not 3 yet? Stone 3 is an AGS000 and not GIA XXX as the other two so it could have a different/better look the previous two stones. However, by your first statement that you can't see a difference in stone 1 and stone 2 with that vast of a difference makes me wonder if you'd notice any difference anyhow.

I would agree it's possible a GIA XXX stone to be as beautiful as an AGS000 stone, as long as the proportions, etc are correct. Also, I would agree it's less time consuming to buy an AGS000 stone than sort through the sea of bad XXX stones.

But if your choices are limited, you must do what works. And with filters, etc on searches it's not quite as bad finding good ones. The bigger issue is most consumers don't know excellent doesn't really mean excellent and lacks the knowledge to filter and search by ideal parameters to find such a XXX stone.

 

[kmoro]

I’d like to suggest you do your searches on each vendors’ site as well ... I noticed that JA AGS stones in virtual inventory don’t show up on the Pricescope search function ... at least not for me, lol, and it’s possible I did something wrong, but ....

 

[hearts-arrows_girl]

Kmoro, I will try that.

 

[JustinL]

I'm a little confused. Are you saying the 0.3ct stone with a 4.5 HCA (stone 1) looked as good as the 0.50ct stone with 1.5 HCA (stone 2)?

Also, if I'm reading correctly, you only received stones 1 & 2, and not 3 yet? Stone 3 is an AGS000 and not GIA XXX as the other two so it could have a different/better look the previous two stones. However, by your first statement that you can't see a difference in stone 1 and stone 2 with that vast of a difference makes me wonder if you'd notice any difference anyhow.

I would agree it's possible a GIA XXX stone to be as beautiful as an AGS000 stone, as long as the proportions, etc are correct. Also, I would agree it's less time consuming to buy an AGS000 stone than sort through the sea of bad XXX stones.

But if your choices are limited, you must do what works. And with filters, etc on searches it's not quite as bad finding good ones. The bigger issue is most consumers don't know excellent doesn't really mean excellent and lacks the knowledge to filter and search by ideal parameters to find such a XXX stone.

Hi @sledge, good day
Firstly, the 0.3ct with HCA 4.5 yes it does look as good (may not be 100% as good though) as 0.5ct with HCA 1.0. I suspect few things. There must be the reason why the GIA grade it as 3EX. Beauty is in the eyes of beholder

Besides, probably the stone size (0.3ct) is insignificant for the untrained eyes (like me) to see the difference even when place them side by side. <—- just my assumptions

I’m not worry on stone number 3 in AGS000 with HCA 1.5 outshine the other two. As I Guess no one will actually study my stone while I’m wearing them.