3 replies to this topic

[rnguyen]

I have been dealing with a local jeweler in finding the right round brilliant cut diamond for an engagement ring, and they finally found one I like.

The problem is it's an EGL graded diamond and I want to know what would be fair market value for it.

It's graded I color and VS2 clarity, I have looked at it under a 10x loupe and cannot see any noticeable inclusions, so definitely to my naked eye I can't see anything noticeable.

As far as the color, the color appears to be accurately graded as I don't really notice a yellow tint, it appears to be on par with the I color GIA graded diamond I received from Blue Nile. I will have to compared the two on Friday to confirm. I saw a few other I color EGL graded diamonds there that definitely had a yellow tint (I realize EGL is in it for profit, but the grading disparity is pretty glaring).

I also looked at it through a Hearts and Arrows viewer and confirmed the H&A designation on the EGL certificate is true, it is nicely aligned and with carefully shaped facets.

It is 1.06 carat, 6.84 x 6.79 x 3.79.
Round brilliant cut
Depth % 55.6
Table % 66
Crown % 11.4
Pavilion % 41.1
None culet
Thin to medium girdle
Very Good cut
VG symmetry, VG polish
Fluorescence : Faint (I verified this as well under a UV light and in sunlight)

The best price I was given was $4500 cash, does this sound right? Does the dimensions I gave along with the percentages match up to a very good cut?

The table and depth numbers don't look right to me, isn't the table % way too large and the diamond too narrow? The diamond itself passes my amateur eye test, but I am not experienced with studying diamonds and have only been looking at them recently. Thanks for any help, I don't want to overpay or make the wrong purchase.

Edited by rnguyen, 25 January 2012 - 01:52 PM.

[denverappraiser]

EGL uses some pretty strange formulas for evaluating cut but what you've got would certainly not be 'very good' on the GIA or AGS scales. Perhaps that's why it was sent to EGL in the first place. You can find lots of EGL graded stones advertised behind the 'diamond finder' link at the top of the page. It's a free and handy way to decide if you're paying a competitive price even if you have no intention of buying from any of these people. If it's what you like it doesn't much matter that it's not what GIA likes but this is decidedly outside of the mainstream.

Edited by denverappraiser, 25 January 2012 - 03:08 PM.

[davidelevi]

You can also use GIA's Facetware cut estimator - available free at https://www.gia.edu/facetware

You will need crown and pavilion angles rather than %, but you can work out an approximation to the angles using some trigonometry or simply play around with the angles and other parameters until you get the right % (the software calculates it).

Out of curiosity, I worked out a set of parameters as follows:

Table = 66
Crown angle = 34
Pavilion angle = 39.6

You can leave the rest of the parameters at their default value, they won't move the result. I'll let you find out what that is, but I think Neil is right on two accounts:

1. The stone was most likely sent to EGL trying to avoid a particular GIA cut grade
2. If you like it, it's fine - but at the very least make sure that you see some "well cut" stones before you buy.

And don't pay cash unless you really trust the vendor...

[rnguyen]

davidelevi, on 25 January 2012 - 04:24 PM, said:

You can also use GIA's Facetware cut estimator - available free at [url="https://www.gia.edu/facetware"][url][url][url][url][url][url][url]https://www.gia.edu/facetware[/url][/url][/url][/url][/url][/url][/url][/url]

You will need crown and pavilion angles rather than %, but you can work out an approximation to the angles using some trigonometry or simply play around with the angles and other parameters until you get the right % (the software calculates it).

Out of curiosity, I worked out a set of parameters as follows:

Table = 66
Crown angle = 34
Pavilion angle = 39.6

You can leave the rest of the parameters at their default value, they won't move the result. I'll let you find out what that is, but I think Neil is right on two accounts:

1. The stone was most likely sent to EGL trying to avoid a particular GIA cut grade
2. If you like it, it's fine - but at the very least make sure that you see some "well cut" stones before you buy.

And don't pay cash unless you really trust the vendor...

I was trying to play with Facetware earlier but couldn't figure out the right angles to get those percentages. I was worried it'd come back fair or good and lo and behold it comes up fair. Thanks for the assistance! Yeah, I definitely will look at some real "very good" cut stones, I just don't see how EGL could have thrown a very good cut grade at it.. I won't overpay and spend that kind of money on something that doesn't have a nice cut.

I agree with you both the only reason this was sent to EGL was to avoid a cut grade from GIA.

Edited by rnguyen, 25 January 2012 - 04:55 PM.