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Crown & Pavilion Angles outside desired range?

H

Hipolito

Rough_Rock
Joined
Apr 20, 2012
Messages
17
Hello, I'm hoping to get some advice about a Round Brilliant I'm looking at. My main concern is that the crown angle is too low and the pavilion angle is a smidge too high, which is going to result in much less sparkle (bang) for my buck. Hoping someone with experience and know-how can advise accordingly?

Weight: 1.37 Ct
Diameter: 7.23mm
Crown Angle: 32.0%
Crown Height: 12.5%
Pavilion Angle: 41.6%
Pavilion Depth: 44.0%
Culet: 0.4%
Table Size: 60.0%
Total Depth: 60.1% / 4.35 mm
Girdle Thickness %: 3.1-3.5 (medium - slightly thick)

Clarity: VS2
Color: I
Fluorescence: None

Appreciate any feedback you may have! Thank you.
 
Hi, and welcome to PS. A couple questions for you:

What lab graded this diamond? In other words, does it come with a grading report from GIA or AGS or EGL?

Do you have the lower girdle facets (lgf) percentage? This is a number printed on the report; you'll usually find it printed on the lower part of the diamond diagram (pavilion) and it will be a number from 70 - 90 %.

Does the grading report (if there is one) assign the stone a cut grade? For example, excellent, very good?

This diamond is what's known as a 60/60 cut https://www.pricescope.com/wiki/diamonds/60-60-proportioned-diamond. These diamonds have a distinctive look to them. Some people love them; other people prefer a higher crown and smaller table. This stone has the potential to be a nice stone. The lower crown and larger table *may* cause this stone to have more smaller flashes of color and white sparkle than larger chunks of fire and white sparkle. Again, that's not necessarily a bad thing. 60/60 stones can look larger for their weight, and may also appear whiter and brighter than stones cut with smaller tables.

ETA: If you look at the diagrams depicted in the article I linked you to above, you'll see that the pavilion angle of your stone is a bit on the high side. This may cause the stone to have light leakage in the center of the stone, which may or may not be visible to your eye.
 
Thanks very much, Lula, that is extremely helpful!

This was in fact graded by GIA. The LGF percentage is 75, and GIA rated it an Excellent cut (excellent polish & symmetry as well).

Sounds like going with the 60-60 stone is an unnecessary risk? I know my girlfriend would like the classic round brilliant in a Tiffany setting, and going with this variation may be too much of a deviation, particularly with the possibility of light leakage due to the higher pavilion angle.

I'd just like to play it safe with a purchase of this magnitude, of course. Judging by the wiki article you sent me, looks like I should probably rule this one out?
 
Can you get an idealscope image of it? That would be the only way to know for sure. But I'd be afraid of that pavilion angle without an idealscope image. I also don't like the look of a low crown and large table...it will look kind of flat from the side.
 
Thanks, diamondseeker. I don't have a Idealscope image, unfortunately. I will try and obtain one, but sounds like I have reason to be skeptical!
 
By the way, the other potential red flag is that the GIA report is from Nov. 30, 2011, so just about 5 months old. So looks like it's been a hard one to sell?
 
I wouldn't rule it out just yet. It was graded as a GIA excellent cut. Diamondseeker is right that the low crown will mean the stone has a flatter profile from the side, which some people don't care for. But, in all honesty, most "normal" (non-diamond-obsessed) people would never notice that. I doubt your girlfriend would notice it.

The lgf's on this stone are a bit shorter than what I'd like to see in a 60/60 stone. It's been my experience, both from reading threads on this forum and from comparing many diamonds in person, that longer lgfs (closer to 80%) may minimize light leakage. But each diamond must be evaluated individually. GIA reports contain rounded numbers, so we're really just guessing on this diamond's appearance based on the numbers alone. Also, many people prefer the look of a 60/60 stone because they often appear visually larger than stones cut to what is referred to as the Tolkowsky ideal https://www.pricescope.com/wiki/diamonds/tolkowsky-ideal-cut-diamond

Are you able to see this diamond in person? Is the price good? Because if you can see it in person, you can judge the optics fairly easily by comparing it to other diamonds under a variety of lighting conditions. What you want to avoid is a diamond with a dull, dark center, or a dark ring around the center. You also want to check for dullness and darkness around the outer edges of the stone -- light leakage can occur at the edges of a stone and that makes the stone look smaller. Make sure you look at the stone away from the spotlights of the store. Look at it in a dimly light hallway away from window; near a window, and outdoors. Is the sparkle uniform throughout the stone? You should be getting sparkle from all parts of the stone as you move it around. Compare this stone to as many other diamonds as you can. Compare it to other GIA excellent cuts with different proportions, and compare it to GIA very good cuts.

But don't rule it out just because there are some of us who prefer higher crowns and smaller tables! Yes, it's important that you get a well-cut diamond, but those come in many flavors. I owned a diamond with a high crown and small table that always looked a little dark to me, not because of light leakage, but because of the fact that the stone was cut to show a lot of large, rainbow flashes (which it did). But that came at the expense of some brightness and white sparkle.

ETA: A GIA report dated in 2011 is not an old report, so no worries there.

ETA: Take a look at this article https://www.pricescope.com/journal/laboratory_cut_grades_what_report_doesn’t_show for an excellent explanation of the differences in appearance between diamonds with the same cut grade. Look at stone number 4. It is an example of a well-cut 60/60 diamond. I would love to own this stone! Take a look at the other stones, and note how the light leakage (shown as white or grey areas in the Idealscope images) affects the look of the diamonds. Compare stone #4 to stone #'s 3 and 5. Those are leaky, poorly-cut 60/60 stones that will look dark and dull in the center and dull around the outer edges. They are quite unattractive stones in real life -- the leakage around the center and the outer edges of the stone is very evident if you set the stones on a red or black cloth -- the color of the cloth will show right through the stone.
 
Thanks so much, Lula -- this is extremely helpful!

I'm unfortunately not able to view the stone in person, but since it's fully bonded, I've been assured that it's a Class II stone and therefore doesn't have the potential light leakage problems you brought up. Does that hold water to you?

The price I've been quoted is $16,900. Do you think that's a good price considering it's also bonded? Or should I try insisting on an Idealscope image to be sure?

Your guidance is much appreciated!
 
Hipolito|1335014520|3177087 said:
Thanks very much, Lula, that is extremely helpful!

This was in fact graded by GIA. The LGF percentage is 75, and GIA rated it an Excellent cut (excellent polish & symmetry as well).

Sounds like going with the 60-60 stone is an unnecessary risk? I know my girlfriend would like the classic round brilliant in a Tiffany setting, and going with this variation may be too much of a deviation, particularly with the possibility of light leakage due to the higher pavilion angle.

I'd just like to play it safe with a purchase of this magnitude, of course. Judging by the wiki article you sent me, looks like I should probably rule this one out?
Click to expand...


Hi Guys- just a general note- that "article" on 60/60 is extremely misleading in it's presentation.
It's a relic of an old argument.
Hip- there's 0 risk - per se- in buying a GIA graded EX cut grade diamond of 60/60 proportions
 
Hipolito|1335206405|3178600 said:
Thanks so much, Lula -- this is extremely helpful!

I'm unfortunately not able to view the stone in person, but since it's fully bonded, I've been assured that it's a Class II stone and therefore doesn't have the potential light leakage problems you brought up. Does that hold water to you?

The price I've been quoted is $16,900. Do you think that's a good price considering it's also bonded? Or should I try insisting on an Idealscope image to be sure?

Your guidance is much appreciated!
Click to expand...
what does bonded mean?.. :confused:
 
Thanks, Rockdiamond!
 
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