shape
carat
color
clarity

What do you think of this diamond?

ok, I'm no round expert, but daaaaaaammmmnnnn. that's one big rock.
 
It had good numbers and with VS1 G should be clean and very white. But, you need to request an ASET and have that evaluated. If graded by AGL, it would be a solid Excellent, but not Ideal. Very much worth pursuing...

If you post your wants and budget we can see if there are other options.
 
Can you tell me what an ASET is? Why does it rank Excellent but not ideal?
 
An ASET is a way of lighting and viewing a diamond to.show its light performance. If you post the image they send. We can help.you read it.
Read this. https://www.whiteflash.com/about-diamonds/diamond-education/about-aset.htm
AGS grads cut in narrower parameters than GIA (GIA is stricter on color). For it to hit AGS ideal, the Pavillion angle would have to be a bit steeper.
If you look at this chart, you flip to the page with the matching table % then use crown and pav angles. GIA rounds the angles, so this is not petfect without some mentail math. Lookup AGSL cut proportion chart, it's a .pdf.
 
Got it. Thanks!
 
I think for that amount of money you should be provided with - an ASET, an Idealscope, a video......and a picture! No diamond comes down to pure stats, you have to see if it speaks to you.
 

I believe this is what @rockysalamander is pointing out:
IMG_8148.PNG
This is how the angles are calculated on the HCA Tool. Certainly not suggesting you rule it out, but rather, investigate further. A diamond of that size is going to have to be nearly flawless in clarity, depending on the type & location of inclusions because the larger the stone, the easier it is to see imperfections. If you are looking for an ideal or super ideal cut, then you must have the correct proportions and angles in order to achieve that quality.
ASET & IS + video will assist you in determining how well cut and clear this stone really is to YOUR eye. Never purchase a stone when all you have are the specs on paper. If my DH and I had based our search for my Center stone strictly on specs on paper, I still wouldn't have an engagement ring...lol!! I never settled, and neither did he. We just got extremely lucky.
If you had to prioritize the 4c's, based upon YOUR preferences, how would you list them?
This is important for us, in order for us to assist you, knowing what YOU are looking for in a diamond vs. what WE would be looking for in a diamond. ;)2
On PS, cut is King, but perhaps, you are more focused on both Cut and size? Are you color sensitive? Do spots on a window or on your phone screen bother you?
These are all helpful tips to help you consider this stone...and any others.
Question: how do you wish to set it?
 
I have seen it. But admittedly I am older and my eyes aren't what they used to be. Eye clean is important to me. I don't want any black specs. Also, G is my minimum color and I don't want fluorescence. I am going to set in a classic Harry Winston with tapered baguettes.
 
I have seen it. But admittedly I am older and my eyes aren't what they used to be. Eye clean is important to me. I don't want any black specs. Also, G is my minimum color and I don't want fluorescence. I am going to set in a classic Harry Winston with tapered baguettes.

An elegant prong setting may help hide any of the inclusions, based upon their location. From the GIA cert, it appears most of the inclusions are in prong range. ;)2
 
This is the AGS Proportion Chart I mentioned.
https://agslab.com/docs/pbcg/AGSLProportionCharts.pdf

A few more contenders. Many larger carat diamonds will tend to be deep, but here are a few that balance the proportions with good angles to generate more fire. All these need an ASET or Idealscope image (ASET is preferred). I opened your parameters to SI and H to find more options. With BN, hold shift or ctrl while you click.

https://www.bluenile.com/diamond-details/LD07113994 (4.11 H SI1, 10.28 mm; bright white and perfect clarity; chubby arrows a plus forme}
https://www.bluenile.com/diamond-details/LD09462748 {4.07 H VS2, 10.36 mm; this has chubby arrows, which I love}
https://www.goodoldgold.com/diamond...GIA-G-VS2-diamond-stock-14218-cert-7201021076 {3.85 ct, G, VS2, 10.08 mm; this would be my personal choice over all posted, provided the size is not an issue, but read below about custom cutting)

Most of us are using some version of the below table to select diamonds that have good potential. Then, some will run them through the HCA tool (as shown by @Matthews1127). That tool will see if the angles are complimentary (keep anything under 2.0). The HCA tool has some assumptions, including a dislike of 60/60 stones. Large carat weight diamonds are often 60/60 type stones, so use it with caution at this size range as you could eliminate stones that have potential. I also look at the AGSL Proportion Chart for GIA stones and aim for Ideal or one of the Excellent options abutting. Those are both coarse filter tools intended to weed out the diamond to those with potential. Then, you look at the Idealscope Image or ASET (preferred) to see actual performance. Also, look at the spread of the diamond (size in mm) not just the carat weight. The faceup size is what you will actually see and sometimes the lower carat weight is not the largest face-up (compare the 4.11 and 4.07 above).

These are measurements to help you stay in ideal cut territory.
table: 52-58
depth: 60-62.3
crown angle: 34-35.0 (up to 35.5 crown angle can sometimes work with a 40.6 pav angle)
pavilion angle: 40.5-40.9 (sometimes 41.0 if the crown angle is close to 34)Another option to consider is reaching out to one of the super-ideal vendors and inquire about a custom cut stone. It will be more per carat, but you get a guarantee of performance and outcome. But, it does eliminate the "hunt".
HighPerformanceDiamonds
Brian Gavin
Whiteflash
GoodOldGold
 
Want closer to 4.5, no lower than G and no fluorescence.
 
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