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Thoughts on this Diamond?

cypress123

Rough_Rock
Joined
Jan 21, 2016
Messages
5
I was looking to purchase the diamond in the attached GIA report which I have seen in person and there are no visible inclusions on the table. Asking price was $12,750. Thanks in advance for the input.
 

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Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
Can you return it?

The angles are not good.

Here's what you need to know.
Round Diamonds 101:

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. With round diamonds even a GIA triple Excellent is not enough. And you must stick to GIA and AGS only (HPD in Europe is good as well). EGL is a bad option: [URL='https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/']https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/[/URL]
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 generally, though you can. In general, AGS0 trumps HCA though as one examines the actual stone and the other does not.
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.
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. BGD,BE, James Allen, GOG, HPD, ERD and WF do.

The Idealscope is the 'selection tool'. Not the HCA.
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. Some AGS0's are better than others though, so pay attention to any ASET or IS provided.

In general with rounds, you will want a table 60% or less. A depth between 59 and 62.4. Crown angle 33.5-36. Pavilion Angle: 40.6-41 (there is a little give on this). And the crown and pavilion angles must be complimentary which is what the HCA checks for you.

ON COLOR:

It is important to remember is that color is graded FACE DOWN. Where there is NO light return. Not face up where there is light return and refraction. You wear diamonds set. FACE UP.

Within one color grade, even the labs can't agree on the color grades of stones and something could be a "high" H or a "low" E. So... no. Not really. Within 2 color grades it is hard. Not impossible. But very hard. And it gets harder once set. If you are talking ideal rounds, or any stone with ideal light return and no sharp corners it gets harder still because the ideal light return masks body color.

Generally we say to be conservative stay above H in a round. But MANY people have happily bought white I or even J diamonds when trying to eek out a little more size.

This is how I think of it.

Ever gotten one of those HUGE paint fan decks? Where there are literally 100s of colors of whites? And when they are RIGHT next to each other you can TOTALLY tell that one is bluer/colder and one is a bit warmer and which one is one is TOTALLY warmer. One there's one that's slightly greener. One that's slightly pinker? But really. They are all white?

Then you pick one after agonizing over this white or that white and when it's on the walls and people are like: Oh. You painted again. And it's STILL white. Great.

And you're all... BUT it's BLUE white. Or it's a WARM white now. It used to be ____ white. It's TOTALLY different.

It's like that. You are talking about shades of white. D is colder... J is warmer. But it's all white.

YES. If you have an accurately graded F and an H THAT HAVE THE SAME PERFORMANCE you are going to be able to tell them apart when you compare them. Just like you would be able to tell if you painted your walls a warm white, but painted the crown molding a cold/straight white. But both are STILL white.


I want you notice all the qualifiers thought. I'm talking about stones with the SAME performance. An ideal H will out white an F that has compromised light performance from a poor cut.

NOTHING impacts the appearance of a diamond as much as cut. CUT is king.

You want the shinest whitest and brightest diamond out there: Cut is King. No other factor, not color or clarity or anything else impacts how white bright an shiny a stone is.

ON CLARITY:
http://www.goodoldgold.com/4Cs/Clarity/SI/ and http://www.goodoldgold.com/4Cs/Clarity/VS/ Generally we say that eyeclean SI1 and VS2 are as high as you need to go with round brilliants, have your vendor check the diamond for this. VS1 will always be eyeclean, but they do cost more and an eyeclean SI1 and a VS1 will look the same to the unaided eye.
 

centrifuge41

Rough_Rock
Joined
Nov 7, 2015
Messages
25
Pavilion angle 41 degrees usually pairs better with a shallower crown angle. But here, the crown angle is 35.5. Not a great pairing.

Run your stone through HCA. It gets 4.1. You'll want to look for <= 2.0 before doing further analysis on those stones. You're looking for "Excellent" for light return, fire, and scintillation. "Very Good" for spread is fine.
 

Dancing Fire

Super_Ideal_Rock
Premium
Joined
Apr 3, 2004
Messages
31,540
This is what PSers refer to as a steep/deep cut.
 

novellevon

Rough_Rock
Joined
Jan 28, 2016
Messages
3
@Gypsy Very informative. Question though, if the GIA certificate for the first one shows the Cut as Excellent but the angles essentially make the cut not so, what is the GIA Cut Grade measuring really?
 

Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
novellevon|1454032918|3983311 said:
@Gypsy Very informative. Question though, if the GIA certificate for the first one shows the Cut as Excellent but the angles essentially make the cut not so, what is the GIA Cut Grade measuring really?

That is not an easy question. Essays have been written on the topic. On PS. In dozens of threads. You want an answer to that, then I suggest you get really well acquainted with the search function and google those old threads for yourself and read up. :read:


That new AGS one you posted is better. But not all AGS diamonds are created equal. Some are better than others. If the vendor can provide a REAL ASET or Idealscope of the stone (not the computer generated one), I would advise that you ask for one and post it.

What are you parameters and are you open to buying online. We can search and see if anything nice pops up.

In ge
 

Diamond_Hawk

Brilliant_Rock
Trade
Joined
Apr 8, 2014
Messages
1,221
novellevon|1454032918|3983311 said:
@Gypsy Very informative. Question though, if the GIA certificate for the first one shows the Cut as Excellent but the angles essentially make the cut not so, what is the GIA Cut Grade measuring really?

I am making no comment about the specific diamond in question, but can answer - in general - about the question of GIA Excellent Cut. The parameters for Cut for GIA were set in order to respond to market demand for that information. This is good for the consumer.

But do consider that GIA relies on diamond sellers for their business - sellers want diamonds graded by trustworthy labs (like GIA and AGS) when presenting their inventory to the customer. So, while GIA's parameters for cut are helpful - GIA also does not want the diamond sellers to submit diamond after diamond and be unsatisfied with the assigned grade; Many people find a diamond graded "Good" (even when dramatically discounted) less desirable than a diamond graded "Excellent"

So - as with any grade (like one assigned in school) - all items within a particular range are not equal. Using the school example, a student with an 89.5 average has, technically, an "A" grade- so does a student with a 99.9 average. Are they equal?

This is why most PS members will recommend a light performance image (Real ASET or Ideal-scope Image) to determine light performance even with diamonds possessing the same cut grade.
 
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