Help me decide between the two diamonds

[wyt]

I am planning to buy a diamond for a proposal ring and I have narrowed down the choices to two diamonds. I manage to get their ideal scope images and sarin reports but I''m stuck in a dilemma over which diamond to buy.

1. GIA 0.85ct G VS2
Depth: 62.3%
Table: 54%
CA: 34.5 deg
PA: 41.0 deg

2. AGS 0.85ct E VS2
Depth: 62.1%
Table: 56.1%
CA: 35.2 deg
PA: 40.9 deg

The ideal scope image of the AGS diamond shows that there are some light leakages at the table (between the 2nd, 3rd and 4th arrows) and the girdle which worries me. But at the same time the GIA diamond has more pronouced distortion and misalignment of the arrows. To make it even more confusing, there are some differences in the cut proportions given by the GIA, AGS and sarin reports. Normally this wouldn''t be a problem if the differences are very small. But these minute differences produce very different HCA scores for the AGS diamond. If I were to use the values from the AGS cert, the diamond scored 2.5 (VG/VG/VG) on the HCA. If I were to trust the sarin report, the diamond scored 1.8 (EX/EX/VG) on the HCA. That is a huge difference in HCA score for only a 0.1 deg difference in CA and PA. Now I''m left confused

. I would like to hear your opinions on these.

 

[wyt]

The top is the GIA diamond and the bottom is the AGS diamond

 

[wyt]

GIA diamond sarin report

 

[wyt]

AGS diamond sarin report

 

[jstarfireb]

I don''t have the expertise to help much, but I can offer one observation. It looks like the 2nd diamond (AGS) is tilted a little in the IS image, because the entire right side of it is lighter than the left. At any rate, if it got AGS0, it''s probably a beautiful stone...

 

[jleb]

If your not a cutter, i doubt you''d figure this one out! You have two issues going for you in a SRB (single round brilliant) design. The first part is the angles on the pavilion. We''ll ignore the crown for now. The second, which most people don''t know about , but which you noted, is the rotational accuracy of the facet placement. The diamond is rotated around it''s central axis as each facet is cut. Faceting machines( for color, which cuts srb stones) use a gear system, such as one w/ 96 teeth. Then for pavilion breaks, your going to have one every 6 notches on the gear, so one at 3, 9, 15, 21 etc.. In otherwords the diamond is rotated 6/96th''s of a circle or 22.5 degrees for each of the break facets.

Now diamonds are cut by eye for the most part. Some cutters do use machines. What you are seeing is the rotational and meet point mis alignment in the stones showing up in your scan. In otherwords, to have all the facets meet at a sharp point, some over and under cutting of the facet was done in order to bring them in. So a facet may be too wide or too narrow, or narrow towards the tip or the base, and all or any of these factors will cause your H&A''s to mis align. Now your ags might have a better score, but if you look carefully, you''ll see the culet is mis-aligned with the table, being moved a bit to the right. If the stone were tilted, we''d see some oval creeping into the table outline, which I don''t see.

I''d take the GIA stone even with that facet over/undercutting, because while that is not perfect, it''s no where near the impact on performance, an offset culet is going to have.

All the errors your seeing in both stones result from facet mis-alignment and cutting errors. It''s not easy making it perfect, hence these imperfections show up.

 

[Lorelei]

I agree with John, the GIA diamond looks better to my eyes, the other is a bit towards steep deep territory, do you have the diameter measurements, girdle, polish and symmetry also please? And also the pics of the actual diamonds? They are both well cut diamonds, but if you want a true hearts and arrows diamond then consider A Cut Above brand from Whiteflash.

 

[wyt]

Thanks for your insight and expert opinion jleb! I had to read your post twice to completely understand what you mean but it was worth it. I noticed there is some pinkish areas around the 3 o''clock arrow shaft. Is that an indication of light leakage?

Lorelei, I would love to buy an aca from WF but they do not have similar sized aca diamonds in stock. The next nearest diamond size is at least 1ct and they costs twice as much. The two diamonds here are also from WF though. Back do the diamonds, are you referring to the diameter measurements and girdle from their GIA and AGS certs because the sarin reports above have them too. The polish and symmetry for the GIA and AGS diamonds are excellent/excellent and ideal/ideal respectively.

Here''s a pic of the GIA diamond

 

[wyt]

AGS diamond

 

[Lorelei]

Yep, I scrolled down and missed the sarins - not enough coffee - sorry!

Ok, I wasn't sure whether you had considered ACA, but I understand about the pricing and availabilty etc. The pics of the diamonds look great, what I would do is contact WF and ask them to pull each diamond and talk you through the pros and cons of each and if possible, get Brian's opinion as to which diamond might be best for you. Also do you have a preference concerning colour etc?

 

[honey22]

When I was searching for a stone, WF didn''t have any ACAs in my specs either. I just contacted Lesley with what I wanted, and the next time Brian was out hunting for new stones for the ACA line, he found one to my specs. They quite often get new stocks and many of these are sold before they go online. This is how I purchased mine, it was sold to me before the info was even loaded up on the site.

If you are really keen on one, give them a call or email them, they might have a listing of new stones coming in soon, or would be able to give you a rough idea maybe of when new ones will arrive. You just never know when the perfect stone will pop up.

 

[Ellen]

Date: 8/9/2008 5:56:12 AM
Author: wyt
Thanks for your insight and expert opinion jleb! I had to read your post twice to completely understand what you mean but it was worth it. I noticed there is some pinkish areas around the 3 o'clock arrow shaft. Is that an indication of light leakage?

Lorelei, I would love to buy an aca from WF but they do not have similar sized aca diamonds in stock. The next nearest diamond size is at least 1ct and they costs twice as much. The two diamonds here are also from WF though. Back do the diamonds, are you referring to the diameter measurements and girdle from their GIA and AGS certs because the sarin reports above have them too. The polish and symmetry for the GIA and AGS diamonds are excellent/excellent and ideal/ideal respectively.

Here's a pic of the GIA diamond

No. That's just the diamond picking up color from something around it (they do that), possibly the photographers shirt. No worries there.

ETAI may have misunderstood, if you are talking about the IS pic. I was talking about the actual pic!