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Help Please - Quality or not?

him21

Rough_Rock
Joined
Nov 16, 2015
Messages
6
Hey There!

I'm currently in the process of buying a diamond. A diamond cutter has offered me this stone at about $3700. These are the specs:

ROUND BRILLIANT

Measurements 6.31 - 6.34 x 3.77 mm
Carat Weight 0.91 carat
Color Grade I
Clarity Grade VS2
Cut Grade Very Good

PROPORTIONS

Depth 59.6 %
Table 62 %
Crown Angle 33.5°
Crown Height 12.5%
Pavilion Angle 41.6°
Pavilion Depth 44.0%
Star Length 50%
Lower Half 75%
Girdle Thin to Slightly Thick, Faceted, 3.0%
Culet None

Please can you assist me with the following questions:

1. Is the diamond a good quality diamond?
2. On the GIA certificate it states "Cut grade affected by brillianteering", what does this mean? Is is a concern? and will it reduce the value of the Diamond?

Would really appreciate the help, just looking for a simple diamond that sparkles:)
 

flyingpig

Ideal_Rock
Premium
Joined
Nov 7, 2015
Messages
2,941
That's neither a quality stone or a fair price for "very good" cut.
I cannot see anyone in this forum, recommending "very good" cut. "Excellent" is almost always the minimum.

https://www.pricescope.com/tools/hca
Follow this link and see what you get for HCA score. A quality stone scores less than 2.0. I have not seen such number before. I won't spoil the result :dance:

"Very Good"
http://www.jamesallen.com/loose-diamonds/round-cut/?CaratFrom=0.90&CaratTo=0.92&Color=I&Clarity=VS2,VS1&Cut=Very%20Good&PriceFrom=&PriceTo=&ViewsOptions=Images&advancedParameter=CaratSliderTop&showAdvanced=show&Polish=&Symmetry=&Lab=GIA&Flour=&DepthFrom=45&DepthTo=80&TableFrom=50&TableTo=83

These are what you are potentially buying, instead of..

"Excellent" (I am not recommending this stone. This is just to give you a visual reference)
http://www.jamesallen.com/loose-diamonds/round-cut/0.91-carat-i-color-vs2-clarity-excellent-cut-sku-712380

Regarding, question 2. please use the search function. or google.
 

Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,225
THat's a terrible stone. I hope you got the table and depth measurements wrong! Because if those are measurements then that dealer is really looking out for himself not you.

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. And you must stick to GIA and AGS only. 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? Well first you want to stick to stones that have a crown angle of 34 (33.5 okay for 60/60 style stones) and over, a pavilion angle of 41 and under, and no deeper than 62.4
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.
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, 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.
 

Dancing Fire

Super_Ideal_Rock
Premium
Joined
Apr 3, 2004
Messages
33,852
him21|1447739634|3950657 said:
PROPORTIONS

Depth 59.6 %
Table 62 %
Crown Angle 33.5°
Crown Height 12.5%
Pavilion Angle 41.6°
Pavilion Depth 44.0%
Star Length 50%
Lower Half 75%
Girdle Thin to Slightly Thick, Faceted, 3.0%
Culet None

Please can you assist me with the following questions:

1. Is the diamond a good quality diamond?
No!, big table, flat top, deep bottom half = :knockout:
 

Diamond_Hawk

Brilliant_Rock
Trade
Joined
Apr 8, 2014
Messages
1,228
him21|1447739634|3950657 said:
2. On the GIA certificate it states "Cut grade affected by brillianteering", what does this mean? Is is a concern? and will it reduce the value of the Diamond?

him21,

In answer to this question, brillianteering refers to the approaches taken in the final stages of polishing. Sometimes the polisher, in order to create a desired effect or angle, will change the thickness of the girdle where either the half-junctions or the main junctions meet. By "painting" - shifting the upper and lower facets towards the main junctions, or "digging" - shifting the upper and lower facets toward the half-junctions they can effect the descriptors (such as average girdle thickness), light performance and/or carat weight of the diamond among other things.


This is an in-depth article on the practice as it relates to super-ideal diamonds:

https://www.pricescope.com/journal/visible_effects_painting_digging_superideal_diamonds
 
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