3 ct decision!

[bsh003]

Hi all,

Need some help here. Please look at the two 3 ct diamonds in the attached pics. One is a G/SI2 and the other is a I/VS2 - the left diamond in the first pic is the same one as the bottom diamond in the second pic.

What diamond looks better to all of you?

Thanks so much for the help!

 

[ecf8503]

Can't tell a thing by the pics. Who certified the stones? Can you post the specs (table and depth%, crown and pavillion angles)? Can you get idealscope images for them? I wouldn't spend that kind of money on a stone that wasn't well cut, and that is what we need to determine.

 

[MissGotRocks]

I agree - we need more info. One is set and one isn't - that makes a difference too. Does one stone have fluorescence?

 

[Tekate]

the one on the right looks nicer to MY eye.. but you need the stats to ensure that you can eliminate one or both.

 

[makemepretty]

Just going by appearance the unset one seems pretty in the pictures. Pictures are not always accurate though. Which one did you think was whiter, sparkly and eye clean in person?

 

[JulieN]

My guess is going to be neither once you post the full details.

 

[bsh003]

Both are GIA, the one that has been set is the G/SI2 and the one on the right is the I/VS2

The specs on the G are: table: 59%, depth: 62.9%, crown angle: 36.0, pavilion angle: 40.8 with faint fluoro. GIA is VG, EX, EX.

The specs on the I are: table: 58%, depth: 64.8%, polish and symmetry are VG, and no fluoro - since this stone was graded before 2006, there no cut grade not pavilion or crown angles on the report - is there a way to estimate these?

Oddly the I looks whiter to me than the G but could the difference be because one is set and the other is not?

If you had to choose between the two, which one and what is a fair price for either stone?

Thanks!

 

[thecat]

From the specs, both are not well cut. Can you please the jeweler for other diamonds? Tell him you want something with good performance.

 

[Gypsy]

Neither. Julie was right. Both are straight passes.

The entire purpose of faceting a diamond is to reflect light.
How well or how poorly a diamond does this determines how beautiful it is.
How well a diamond performs is determined by the angles and cutting. This is why we say cut is king.
No other factor: not color, not clarity has as much of an impact on the appearance of a diamond as its cut. An ideal H will out white a poorly cut F. And GIA Ex is not enough.
So how to we ensure that we have the right angles and cutting to get the light performance we want?
https://www.pricescope.com/wiki/diamonds/diamond-cut
Well one method is to start with a GIA Ex, and then apply the HCA to it. YOU DO NOT USE HCA for AGS0 stones.
https://www.pricescope.com/wiki/diamonds/holloway-cut-advisor
The HCA is a rejection tool. Not a selection tool. It uses 4 data points to make a rudimentary call on how the diamond may perform. It's only goal is to weed out stones that have angles that do not normally result in ideal light performance.
If the diamond passes then you know that you are in the right zone in terms of angles for light performance. Under 2 is a pass. Under 2.5-2.1 is a maybe. 2.6 and over is a no. No score 2 and under is better than any other.
Is that enough? Not really.
So what you need is a way to check actual light performance of your actual stone.
That's what an idealscope image does. https://www.pricescope.com/wiki/diamonds/firescope-idealscope
It shows you how and wear your diamond is reflecting light, how well it is going at it, and where you are losing light return. That is why you won't see us recommending Blue Nile, as they do not provide idealscope images for their diamonds. James Allen, BGD, GOG, ERD, HPD and WF do.

The Idealscope is the 'selection tool'. Not the HCA. The HCA is just used narrow and predict which stones will have a good idealscope image.
So yes, with a GIA stone you need the idealscope images. Or you can buy an idealscope yourself and take it in to the jeweler you are working with to check the stones yourself. Or if you have a good return policy (full refund minimum 7 days) then you can buy the idealscope, buy the stone, and do it at home.


Now if you want to skip all that... stick to AGS0 stones and then all you have to do is pick color and clarity and you know you have a great performing diamond. Because AGS has already done the checking for you. That's why they trade at a premium.

 

[Gypsy]

If you are working in person, give this to your jeweler and tell him to stick to it. From Lorelei:

depth - 60 - 62% - although Lorelei's personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!