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luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
Here is a description of a diamond that I'm considering.
GIA Certified Round Brilliant
1.27 carat
E color
7.01-7.09 x 4.30mm measurements
Depth 61.0%
Table 55%
Girdle: Thin to medium, faceted
Culet: None
Polish: Very Good
Symmetry: Good
SI2
Faint Fluorescence
Comments:
Additional twinning wisps are not shown.
Surface graining is not shown.

The following info was not on the GIA report, but it is accurate:
Crown angle: 32.4 degrees
Pavilion angle 41.6 degrees

I've seen the stone, and it is indeed eye clean. The plot notes only twining wisps, which as I stated are not visible without a loop, but with a loop there are a number of them, although mostly towards the sides fo the stone with a few that make it out towards the table a good bit.

What are your thoughts on this stone?
I asked the jeweler for only ideal cut stones. The depth and table definitely fall in the ideal category, but if you look at the crown and pavilion angles, I seem to be falling towards an AGS 2 cut grade (not ideal--the jeweler did not origionaly know the crown and pavilion angles ; I obtained the crown and pavilion angles on my own).

Should I not really worry about the crown and pavilion angle and assume that it is indeed pretty much ideal? Any thoughts/comments are apreciated.

By the way, if it matters, I'm able to get this stone for $5,500 total including out of state shipping (I live on the stateline, which is why I'm able to see the stone).
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
Luckyguy: the price sounds very good indeed.

Garry: interestingly, despite of partial light leakage, Diamond Calculator shows very dicent (>1) light return even under the table.

What do you think?

 

luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
You guys are great getting back to me so quickly. I am still waiting to see what you continue to say about this stone. Looks like there are some interesting results.

Leonid: I am not able to see the picture of the Luckyguy.gem file that you put in your last post where you said "I attached GemAdviser file for this stone: Luckyguy.gem."

How can I access this file?

Thanks guys...

Keep the comments comming. I love this site...can you tell I'm a newbie (besides the fact I've only made a couple of posts)? For all you veterans, I hope you haven't lost that "this is a great forum" feeling.:))
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,362
LG:

You have gotten a pretty decent set of answers here. The stone is not perfect, but it is no slug, either. There are far many more of these very good stones than ideal cuts being worn happily by many people. With a slight compromise in size, etc, you could afford a better cut stone that might look quite similar in size white the various performance predictions might please you better.
 

luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
Thanks for the response guys; It seems like I've got a pretty nice stone for the price. I am curious what Cut Nut's comments are with regard to the Gemapraiser results in conjunction with the HCA results.

Regards...
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,926
Hmmmm
I think the grey circle area (partial leakage in the table region) would worry me. It would look a little like a fish eye.

Hmmm - What do you guys think. The DiamCalc light return is surprising. The red image is a Firescope image. You would not see nice stars like this in the real world. It would be a contrast free stone = little scintillation, except for the darkness from the leakage.
 

luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
Cut Nut,

I will do my best to check for the Fish eye effect on Friday when I check the stone out again.

By the way, What about the stone's measurements is leading you to say that it will be a contrast free stone with little scintilation? The gemapraiser seems to rate this stone as having very good contrast. Furthermore, it rates the "Fish Eye" factor at the high end of very good as well. Am I missing something?

How do I tell if the stone has great scintilation or not when I'm look at the real stone this Friday? Any tips on what to look for with regard to the fish eye effect and scintilation would be greatly appreciated.

Regards...
 

luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
By the way,

I was playing around with the cut advisor and I noticed that if the pavilion angle is changed from a 41.6 degree angle to a 41.5 degree angle that the stone gets a score of Very Good all the way down and receives a score of 2.6 rather than a 3.1 given with the origional 41.6 degree angle.

Maybe this is why the diamond is so finicky. It's right on the border of being considered "Very Good" in every category by the HCA. I don't know...it was just an observation. I'm not sure this is how the HCA should be approached, but I just was checking to see if the measurement for the angle were off by just a bit what would happen. Heck even the GIA measuring these angles may be off by 0.1 degree, right?

Just some observations from a novice...
 

luckyguy

Rough_Rock
Joined
Nov 19, 2002
Messages
37
Leonid,

Cool looking post, but I don't quite understand the graph. I do like all the colors though.

I will take you word for it that a small change in pavilion angle makes a big difference. I guess that raises the question as to the accuracy of the angle measurements. Even though I stated that they were accurate before, I'm not sure they are accurate down to 0.1 degree. I guess YOU CAN'T QUESTION EVERYTHING, or you would never get anything done. So I'll go back to assuming that the 41.6 degree pavilion angle is correct.

With all this in mind, I guess that's why I asked Cut Nut to give some advice on how to physicaly took at these features in a real diamond. I look forward to his and others' advice to assist me when I go back to look at the diamond on Friday.
 

Tee

Rough_Rock
Joined
Sep 25, 2002
Messages
12
Hi Leon,
Would you calculate my diamond for light leakage and light return? I want to know if I should return it. Appreciate the help!
0.93 Square Emerald Cut
5.60x5.50x3.59
Crown H. 14.9%
Table 61.1%
Pavil depth 46.1%
Cutlet 0.4%
Girdle thickness 1.9%
Pavil A. 42.81
Crown A. 37.47
:tongue:
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
LG, Sarin accuracy for measuring pavilion angles is not better than +/- 0.1 degree. And it will make a big difference in HCA and Diamond Calculator results.

Consider them as preliminary filtering though. Final judgment can only be made by live examination of the stone by diamond expert.

Tee, sorry but for fancy shape it is much more complicated and these numbers are not enough for building an adequate model. It does sound like well cut stone though according to AGA chart (www.gemappraisers.com)
 

Serg

Ideal_Rock
Trade
Joined
Mar 21, 2002
Messages
2,472
This diamond has pav. angle from 41.45 to 41.75( if cut is "correct")
See diameter

Leonid20_11_02.gif
 
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