Question About Diamond Cut

[shihtzulover]

Hi everyone,

I am new to this forum, but you all seem very knowledgeable. Maybe you will be able to help me out.

My boyfriend and I are planning to get engaged very soon. We decided that we wanted a princess cut diamond, and then we went looking. We also decided to get a simple, Tiffany-style platinum band. We went to nine different jewelry stores, looked online for lots of information, and looked at Blue Nile.

The more we looked around, the more confused we got about what we really wanted. We started with wanting everything to be completely ideal (most ideal cut, colorless range, VVS clarity, excellent polish and symmetry, etc), but the more we looked, the more we realized that we could find a beautiful diamond with slightly lower ratings. In fact, some of the diamonds that we loved had the lower ratings.

We finally chose our perfect diamond: we went to a well-rated local jeweler and found a 1.53 carat princess cut, F color and SI1 (but totally eye-clean) clarity with excellent polish and symmetry. It is being set in an ultra-thin (1.8 mm) Tiffany-style platinum band. I want the diamond to be what really stands out, and I think this will really make it shine.

Here is what I am confused on. When we got there, the jeweler showed us a book of what we should look for in a diamond. He mentioned that cut ratings range from 0-10, and that a 0 is totally ideal, and that a 1 is premium. He also told us that his store only sold diamonds with a rating of 0-2, since they had high standards relating to cut.

We looked at the GIA cert., and it said nothing about the cut. We asked him, and he looked at the numbers and said that our diamond is a 1 (premium). He also said that there would be no noticeable difference between a 0 and 1 as far as the eye can see.

What on earth is this cut scale? I noticed that one of the independent jewelers we went to before talked about the same scale. Is this the HCA scale that everyone talks about, or something else?

Also, another question: why do some diamonds of the same carat weight look larger than others? Is this determined by the table percentage, or something else?

We examined the cert. before we bought it, but we do not currently have it in our hands because we only gave a down payment while the ring is being set.

Thanks so much for your help!

 

[Todd Gray]

The diamond cut quality grading system developed by the American Gem Society (AGS) Laboratory (AGSL) scores diamonds numerically for (1) Proportions; (2) Polish; (3) Symmetry; (4) Light Performance; and it sounds as if the jeweler you are working with is attempting to cross reference a GIA graded diamond using the system created by the AGS Laboratory. While there are some similarities in grading practices between the GIA and AGS gemological laboratories and it is possible to estimate what the proportions grade of a round brilliant cut diamond might be on the AGS proportions scale (0 Ideal down to 10 Very Poor) by comparing the measurements of the diamond to the AGSL Proportions Chart it is not necessarily an accurate comparison because the measurements stated on a lab report for things such as the crown angle and pavilion angle are averages based on the sum of eight individual measurements and the spread of those measurements might be broad enough that they would prevent the diamond from being labeled that same proportions grade by the AGSL if they were to actually grade the diamond - so it takes a little more insight and knowledge to know whether that is a reasonable assumption or not - but beyond that, there is the fact that princess cut diamonds actually have (2) crown angle and (2) pavilion angle measurements which are then averaged as one on the lab reports; thus I (personally) would not attempt to bridge that gap between the two gemological laboratories (for a princess cut diamond).

 

[ChunkyCushionLover]

Date: 6/30/2010 12:45:11 PM
Author:shihtzulover
Hi everyone,

I am new to this forum, but you all seem very knowledgeable. Maybe you will be able to help me out.

My boyfriend and I are planning to get engaged very soon. We decided that we wanted a princess cut diamond, and then we went looking. We also decided to get a simple, Tiffany-style platinum band. We went to nine different jewelry stores, looked online for lots of information, and looked at Blue Nile.

The more we looked around, the more confused we got about what we really wanted. We started with wanting everything to be completely ideal (most ideal cut, colorless range, VVS clarity, excellent polish and symmetry, etc), but the more we looked, the more we realized that we could find a beautiful diamond with slightly lower ratings. In fact, some of the diamonds that we loved had the lower ratings.

We finally chose our perfect diamond: we went to a well-rated local jeweler and found a 1.53 carat princess cut, F color and SI1 (but totally eye-clean) clarity with excellent polish and symmetry. It is being set in an ultra-thin (1.8 mm) Tiffany-style platinum band. I want the diamond to be what really stands out, and I think this will really make it shine.

Here is what I am confused on. When we got there, the jeweler showed us a book of what we should look for in a diamond. He mentioned that cut ratings range from 0-10, and that a 0 is totally ideal, and that a 1 is premium. He also told us that his store only sold diamonds with a rating of 0-2, since they had high standards relating to cut.

We looked at the GIA cert., and it said nothing about the cut. We asked him, and he looked at the numbers and said that our diamond is a 1 (premium). He also said that there would be no noticeable difference between a 0 and 1 as far as the eye can see.

What on earth is this cut scale? I noticed that one of the independent jewelers we went to before talked about the same scale. Is this the HCA scale that everyone talks about, or something else?

Also, another question: why do some diamonds of the same carat weight look larger than others? Is this determined by the table percentage, or something else?

We examined the cert. before we bought it, but we do not currently have it in our hands because we only gave a down payment while the ring is being set.

Thanks so much for your help!

It is disappointing that you have received so much confusing information.
As Todd has written already it will be difficult to judge the cut of a Fancy shaped diamonds by the numbers at least not the limited ones available on a grading report.

On this forum we prefer images (photograph and ASET) or performance(not proportion) based grading which is only found on AGS DQR or Platinum reports or used by some AGS members through the AGS PGS(performance grading software).

If cut is important to you than I would suggest contacting vendors who specialize in well cut AGS 0 princess stones or ones that show superior optical performance from reflector images like ASET.

Some vendors to consider that offer top performing princess cuts:

1) Whiteflash
2) GoodOldGold
3) HighPerformanceDiamonds or NiceIce (or any Infinity Princess Dealer)

If you have a particular budget and specs post them and myself or others would be happy to find you suitable well cut stones.

Good-Luck,
CCL

 

[shihtzulover]

So does this all mean that this diamond will not have optimal brilliance, or just that you can''t tell?

Thanks so much again!

 

[ChunkyCushionLover]

Date: 6/30/2010 1:20:21 PM
Author: shihtzulover
So does this all mean that this diamond will not have optimal brilliance, or just that you can't tell?

Thanks so much again!

Optimal brilliance usually comes from a branded stone or a carefully selected in house stone. The chance of finding generic stones as good as branded(from the vendors listed above) or AGS0 stones is remote if not impossible. The top performers sell for a premium and any AGS0 princess cuts also trade at a premium.

Any drop shipper like Bluenile who sells non branded virtual stones will not see the diamond before shipping it to you. The chances of finding one with comparable optical performance as above from this or any other drop shipper is remote.

 

[shihtzulover]

Thank you so much for all of your help.

The cut is important to me, because I do want a lot of sparkle. We also decided that we want a 1.5 carat princess cut diamond (or larger, of course), but we do have a price range that we are looking at.

The diamond that we are having set right now is $12,000 even, and the store is throwing in the classic Tiffany platinum setting for free. It is 1.53 carat with F color and totally eye-clean SI1 clarity - even when we were told where the flaw was, we could not find it without the loupe. The table was 71%, and the polish and symmetry were both excellent. Overall, it looked very pretty, and the jeweler also mentioned that they have very high standards relating to the cut of the diamonds that they carry.

We also had a diamond brought in to Jared's. It is $12,900, plus the money for the setting and extended service plan (probably about $14000 for all of this) - the extended service plan is included with the purchase with the first jeweler. I think it is 1.54 carat, but I might be a couple of points off. It has very good polish and symmetry, F color, and VS2 clarity - the table is 74%. The saleswoman there called and said that it is absolutely beautiful, but we have yet to look at it. Up until now, we were planning to just say that we are not interested - unless you think that this is worth looking at.

We are a bit apprehensive about buying online, but we do want that true ideal cut. We want something in the colorless range (my boyfriend and i went and looked at several diamonds, and did not personally like the little bit of color we could see in anything other than the totally colorless ones), so nothing higher than an F (no G, H, I, J, etc). Also, since we can't SEE the diamond if we buy it online, we would want to make sure that it is totally eye-clean before buying it, so we wouldn't want anything less than a VS2. Of course, I would like something with optimal brilliance. I'm not really sure that it is possible to find all of this while trying not to go above $15k total (for the diamond and classic platinum Tiffany setting).

I really think we may have gotten the best possible deal with the first diamond. It is definitely very pretty to look at. Thoughts or suggestions? If anyone could find a diamond with our preferred specs and within our budget, that would be awesome, but I'm not sure that's possible.

Thanks again!

 

[slg47]

1.696 F VS1 ACA princess

this one is just over 15k but is larger than 1.5 ct, also AGS0, simple solitaire settings are not that expensive

 

[shihtzulover]

http://www.whiteflash.com/loose-diamonds/princess-cut-loose-diamond-2262606.htm

What about this one? I have been playing around and looking, and I really want to ask my boyfriend about this one. I see that the color grade is ''H'', but this diamond is a better price and I would rather go down on color than cut.

Also, do you think this diamond would have any visible inclusions? I can''t really see anything bad with the 40x magnification picture.

Does this look like a good deal?

 

[stone-cold11]

Looks good.

Ask WF if the stone is eye-clean, not way to judge from image.