Help please

[FearlessSmile]

I currently have a triple ex diamond table 57 with CA 34.5 PA 41.4 - pav depth 44.0, it sparkles really well in the sun and ok in other lighting. (maybe the deep pavilion angle?) HCA 4.8 and 2B overall AGA/NAGA.

Is this one likely to perform better? It's F colour, VS1, 0.70 carat.

It scores 1.7 HCA and 1A overall on AGA/NAGA tool and fits GIA triple excellent and AGS 0.

Thank-you for your help in advance.

• Length:5.67
• Width:5.70
• Depth:3.52
• Total Depth:61.92%
• Table percent:57
• Crown height:15
• Girdle (from):Medium
• Girdle (to):Slightly thick
• Polish:Excellent / Very Good
• Symmetry:Excellent / Very Good
• Crown angle:35
• Pavilion depth:43

• Tab Percent: 1A
• Crown Angle: 1B
• Crown Height: 1A
• Pavilion Depth: 1A
• Girdle: 1A
• Depth: 1A
• Polish: 1A
• Symmetry: 1A
• TotalGrade: 1A

 

[tyty333]

Can you post the pavilion angle?

 

[FearlessSmile]

Sorry I forgot it didn't include that - it's 40.8 - thanks

 

[diamondseeker2006]

Definitely return the one you have currently. Who graded the second diamond? If GIA, it is not going to have a grade of Excellent to Very Good on polish and symmetry. It technically falls into the measurements below, but I am not sure I'd buy it based on the photo.

These are measurements to help you stay in ideal cut territory with a GIA graded, excellent cut stone.

table: 54-58

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: 40.6-40.9 (sometimes 41.0 if the crown angle is close to 34)

 

[FearlessSmile]

Thank you yes it is GIA excellent cut, polish and symmetry and falls within them parameters

 

[FearlessSmile]

Also managed to work out the exact numbers as I believe GIA round their numbers.
Crown Angle - 34.90(249567)
Pavilion Angle - 40.69(553104)

So more accurately that would read as Crown 34.9 and Pavilion 40.7?

 

[sledge]

Any math you are using to obtain what you believe is "actual" crown and pavilion angle is just an approximation at best.

If you aren't aware, there are 8 crown and 8 pavilion angles in a round diamond. Each angle will vary slightly. How much depends on the precision faceting, or lack thereof.

With each of these 8 values, GIA then averages them and rounds to the nearest half degree for crown and nearest tenth degree for pavilion. Consequently you end up with something like 35/40.8 on the report.

AGS does it similar. They too collect all 8 angles but they just average them (without the rounding) which is why you get values like 34.7/40.7 on AGS certified stones.

These may seem like very small differences, but they can have big impacts. Looking at percentages tells us where they may fall, but again, the most accurate way to know for sure is to get a SARIN report that will show all the angle values. Some of the recommended vendors here will do that for you, if requested.

Moving on. The issue you have with your current triple X stone is the pavilion angle. The 57 table and 34.5 crown is perfectly fine. The 41.4 pavilion is the issue. Generally speaking, at 41.2 and above things get wonky in a bad way. And although you didn't list the depth I am guessing you are above 62.5% as well. Again, this is just looking at angles. More goes into it than that, but it does help us identify some of the issues.

I do think the new stone sounds more promising. What strikes me odd is the "range" you gave for polish and symmetry of EX-VG. Also, your reported depth at 61.92. GIA will either be EX or VG, but not a range like that. Also, GIA reports depth as 61.9, but not 61.92.

I might further add that before jumping in head first, I'd ask the seller for some advanced images like an ASET or idealscope image to confirm light performance. I've helped quite a few people pick diamonds and seen too many 35/40.8 combos that falls in the proportions range recommended but have leakage in those advanced images. So perform your due diligence here before you click buy.

 

[FearlessSmile]

A SARIN report would be great if anyone can help. I'm not sure what you mean about the polish and symmerty?

The option on the AGA/NAGA tool is only Excellent-Very good it doesn't separate them? The depth on GIA cert is 61.8 - Thanks.