Question about this diamond. AGS 0 Grade and HCA of 3.8

[aries2]

Hello Everyone,
I am currently searching for a diamond for my engagement ring and am having a really tough time. I was checking out this diamond and noticed it looks a bit different in the area around the table. I'm not sure exactly what area it's called but the 8 points which make an area of contrast around the table appears more defined than in the other AGS 0's, which I find interesting. I plugged in the numbers in the HCA and it only gave a score of 3.8 with only good performance. It's also out of the AGS 0 range of red color on the HCA graph. Can anyone explain what accounts for the discrepancy between the AGS 0 grade and the HCA of 3.8? For an AGS 0, shouldn't the HCA score and performance be better? With many of the diamonds I'm looking at the grades of GIA ex or AGS id seem to not match up too great with the HCA scores. I know there are limits and infinite variations within these grading systems and with HCA but am I missing something?
Thanks for your help,
CC



http://www.jamesallen.com/diamonds/I-SI1-Ideal-Cut-Round-Diamond-1352965.asp

 

[Garry H (Cut Nut)]

I suggest you request the Ideal-scope image and ask for the stone to be put on hold.
It is possible HCA is a bit harsh since the stone has very good symmetry from the Hearts image.
It might also be helped by a tiny bit of lower girdle painting.
!.3ct stones are not easy to find

 

[Karl_K]

The hca didn't take into account the long lgf% and optical symmetry(hearts look nicely symmetrical but need an IS/ASET/Arrow view) the AGS0 grade did.
I would prefer a slightly shallower pavilion with that crown but AGS software says it works based on scan data.
I would want to confirm that with a real is/aset image which JA can provide.
If it does then from a looks department this diamond would be rather unique with the larger table, steep crown angle and long lgf%.

Due to the long lgf% and proportions many would not consider this diamond H&A but that does not change the fact that if the arrows match the hearts it has excellent optical symmetry.
Some call this type of pattern modified h&a.

 

[Karl_K]

also have them check and see if it is eyeclean.

 

[Ickeymouse]

Gentlemen, What about the picture of the ASET on the AGS cert. Doesn't that tell the buyer anything?

 

[Garry H (Cut Nut)]

Gentlemen, What about the picture of the ASET on the AGS cert. Doesn't that tell the buyer anything?

The AGS software generated ASET black does not enthuse me IM

 

[Karl_K]

Gentlemen, What about the picture of the ASET on the AGS cert. Doesn't that tell the buyer anything?

The AGS software generated ASET black does not enthuse me IM

I agree.
To me it is only good enough to tell if a diamond warrants getting real images.
The image is only as good as the scanned data for the diamond and the scanner used does not always have enough accuracy to give true to life images.

 

[denverappraiser]

I like those images. I agree that it's no more or less than a graphic representation of the Sarin data and that it's not a substitute for a real image but it's presented in a way that's easy to see and get a feel for the way the stone might look in real life. 'Real' images have a different set of issues because they are usually taken under unknown conditions using unknown techniques by an unknown photographer with unknown post-processing. If they're presented in isolation, that's a lot of unknowns to contend with. At least with the AGS model we know who created it, we know how it was created, and we know the limits for what it does and doesn't show.

 

[Ickeymouse]

So , it must be true that any generated image suffers either user/equipment bias? Yes? Sorry for the highjack...

 

[denverappraiser]

So , it must be true that any generated image suffers either user/equipment bias? Yes? Sorry for the highjack...

Yes. Actually that's true of any dataset at all. I also rather like the photographic images as well, but you must see them in context. GOG does not use the same techniques as Whiteflash, who do not use the same techniques as James Allen, who does not use the same techniques as Garry. None of these are 'right' but if you're comparing an image from one aganst an image from another you are subject to discrepancies that have more to do with the photographer than the stone. All of the folks in my last sentence are very careful and consistent about how they take images and they are useful shopping tools, butnot everyone is so contientious. An image provided for evaluation from an unknown, or at least unidentified, source is highly suspect and, in my opinion, of very limited value.

 

[Karl_K]

So , it must be true that any generated image suffers either user/equipment bias? Yes? Sorry for the highjack...

Yes. Actually that's true of any dataset at all. I also rather like the photographic images as well, but you must see them in context. GOG does not use the same techniques as Whiteflash, who do not use the same techniques as James Allen, who does not use the same techniques as Garry. None of these are 'right' but if you're comparing an image from one aganst an image from another you are subject to discrepancies that have more to do with the photographer than the stone. All of the folks in my last sentence are very careful and consistent about how they take images and they are useful shopping tools, butnot everyone is so contientious. An image provided for evaluation from an unknown, or at least unidentified, source is highly suspect and, in my opinion, of very limited value.

With experience one can learn what to look for and achieve a good evaluation.
For example I know what a top stone looks like under gog,wf,ja,Garry's setup so dont need to compare each image to another but to the reference for each I have built up over time.
I also know the weakness and strengths of each setup.
For someone new to them it is a far bigger issue, that is the greatest strength of PS, they can post the images for comments from people who are more familiar with the images.

Even images from an unknown source can be useful as long as one knows what to look for in image variations and how to correct for them if possible.
It is however true that some images are so far off to be useless.

 

[aries2]

Wow, thanks everyone for your responses! So, the longer girdle facets may be what is causing the area of 8 pointed black contrast around the table of the diamond in question? I would take the image and outline it in photoshop but I think the photo is copyrighted so don't want to mess with it. I found this old post about lower girdle facets which is interesting:

[URL='https://www.pricescope.com/community/threads/sorry-stupid-question-what-is-lgf.61176/']https://www.pricescope.com/community/threads/sorry-stupid-question-what-is-lgf.61176/[/URL]

I looks like the diamond in question has something like 80% lgf according to the contrast pattern I'm talking about. I like the looks of about 80% lgf the best I think with the thinner arrow pattern. What pattern do you like the best and which is typically most popular! This is a whole new area of what makes the patterns in diamonds and is really interesting!

So, you think the diamond in my 1st post has an interesting and unusual pattern and that the HCA hay have been overly harsh on it? I think it does too as compared to say something like this one that does not have such an interesting looking pattern. Although it looks like the lgf% on this one are also longer? Or am I wrong? Why does this one not have the pattern/contrast look of the other diamond?

http://www.jamesallen.com/diamonds/I-SI1-Ideal-Cut-Round-Diamond-1349644.asp

Also, you're saying that a painted girdle may have something to do with it? I did some reading about girdle painting but still am not clear about what effect it has on the diamond. Any info would be appreciated!

Yes, I am finding out the hard way that 1.3 ish ct diamonds are HARD to find. Would love something like a 1.7 ish ct but that is currently totally out of my price range. So, 1.3 ct seems to be my next ideal...and even that now is becoming a giant stretch with the recent ballooning of diamond prices. I never should have waited so long to take the plunge and I'm feeling so sad and very frustrated in my engagement diamond search and am feeling like I'm never going to find the right stone for me, especially since I'm looking for a strong blue fluorescent stone also. That seems to be a major limiting factor.

Well, thanks again for the replies and lively discussion...keep the comments coming ; )

~CC

 

[stone-cold11]

No sure what you mean, maybe the table reflection. Do a search on that.

The 1.03c stone has a much lower crown, deeper pavilion compared to the 1.32c stone, main reason for the difference in look.

 

[Ickeymouse]

...and especially since I'm looking for a strong blue fluorescent stone also.

Have you checked out the Brian Gavin's "Blues?" Here is one, don't know about your budget...

1.01 I SI1 Strong Blue Fluorescence

And, thank you gentlemen for your replies about the ASETs that makes a lot of sense!

 

[aries2]

Ickeymouse:

Great suggestion! I just found out about Brian's Blue line yesterday and wish I would have known about it sooner! I could have ended my search months ago. It's great that he has selected stones specifically for their SBF for people like me who love the property.

http://www.briangavindiamonds.com/diamond/diamond-detail/?product_id=BLAGS-104050981003

I asked to have this stone reserved so I can make a final decision. It looks wonderful and has an AGS 0 grade. However, when I ran the HCA it gets a 1.8 and
Light Return Excellent
Fire Very Good
Scintillation Very Good
Spread
or diameter for weight Very Good

and is out of the red outline of the HCA graph. Some other AGS 0 stones I have run have scores of 1.3-1.5 and have all excellent scores and VG for diameter for weight. So, I wonder why it's only getting VG for the other properties. What do you all think of this stone? Should just take the plunge already since I know diamond prices are continuing to go up and risk not being able to get a diamond at all? Despite the VG HCA scores, will this stone be a killer stone next to most other stones? In other words, even though my diamond may be smaller than most of my friend's diamonds, will my diamond knock the socks off their larger but more commonly cut stones

Experts...thanks for all your comment and help!

CC

 

[aries2]

Thanks Ickymouse! I ended up buying your suggested Brian Gavin Blue stone! It is awesome and blows away anything I looked at in stores. I'm waiting for my setting to come in and can't wait to post pics for everyone. Thanks to all who commented to my post; you were all such a big help!

 

[aries2]

Neil: Thanks for your comments. Very interesting info!