Opinions on stone

[TomL]

Hi guys

I have a potential round cut stone here which is a 0.77 ct, GIA EX EX EX, E, SI1 together with the dimensions below, ,could you let me know any opinions of it.

Depth 62.8 %
Table 57 %
Crown Angle 36.5°
Crown Height 16.0%
Pavilion Angle 41.0°
Pavilion Depth 43.5%
Star Length 50%
Lower Half 80%
Girdle Medium to Slightly Thick, Faceted, 3.5%
Culet None

Thanks in advance

 

[pfunk]

Hi guys

I have a potential round cut stone here which is a 0.77 ct, GIA EX EX EX, E, SI1 together with the dimensions below, ,could you let me know any opinions of it.

Depth 62.8 %
Table 57 %
Crown Angle 36.5°
Crown Height 16.0%
Pavilion Angle 41.0°
Pavilion Depth 43.5%
Star Length 50%
Lower Half 80%
Girdle Medium to Slightly Thick, Faceted, 3.5%
Culet None

Thanks in advance

It is what is known as a “steep deep” stone. The angles dont work well. It has a tall crown (36.5 degree) which would need to be paired with a shallower pavilion angle (40.4 - 40.6). Instead the pavilion is at 41 degrees which will lead to light leakage. The total depth of 62.8% is also slightly more than preferred which means the diamond is hiding weight in its “depth” instead of across the crown in its diameter. It will have a lower diameter and be slightly smaller than a well cut stone would.

If you don’t mind... please give the community here some background as to what has brought you here to ask this question. Are you shopping in stores and asking for advice on a stone you have been shown? Are you shopping online? If you would like help getting recommendations please post your budget and your preferences for the diamond you are in search of (cut preference, size, color, clarity, certain vendors, timeline, etc).

 

[TomL]

Hi pfunk

Yes I am shopping in stores and was shown this stone.

Will the light leakage effect be highly noticeable compared to say a very well cut stone like the true hearts stones offered on online stores such as James Allen?

Also, a general question. Would the light leakage be worse on this stone or one at the top end of the VG range other things being equal?

 

[pfunk]

How noticeable it is depends on the viewer. It is a subjective thing. I think you would be best served by asking your jeweler to bring a diamond of more ideal proportions so you can see for yourself. I would try to find the following in a similar size/color/clarity so that you are essentially assessing the cut difference only:
Depth:60-62.3%
Table:54-58
Crown Angle- 34-35 (if 35 shoot for a pavilion of 40.6)
Pavilion Angle- 40.6 - 41(should only be 41 if crown angle is 34)
Girdle-Thin - Medium preferred (slightly thick is ok).

As for the second part, I am afraid this isnt that helpful but again, it depends. There are different reasons for why a stone might fall into the VG cut category instead of excellent. Just because a stone is VG cut does not automatically mean it will be more leaky than any “excellent” cut diamond. There are multiple variables that need to be considered. If you arent already, please use the HCA tool and check any diamonds you are considering in store. It is not a selection tool, rather it is a rejection tool to help you weed out diamonds that are more likely to be poor performers based on their angles. Your stone scores 4.9 and you should be trying to find stones that score 2.0 or less.