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Help - 0.96 VS2 vs 1.00 SI1

Typhon

Rough_Rock
Joined
Jan 30, 2016
Messages
5
Hi all

Have been looking for a stone for roughly 3 weeks and have narrowed it down to these two. They are about the same price.

Carat weight 0.96
Shape Round
Cut Ideal
Colour G
Clarity VS2
Length/width ratio 1.01
Depth % 62.8%
Table % 54.0%
Polish Very Good
Symmetry Very Good
Girdle Medium to Slightly Thick
Culet None
Fluorescence Faint
Measurements 6.24 x 6.31 x 3.94 mm

http://www.bluenile.com/certs/6191985724.pdf?params=Y291bnRyeT1BVVMmcHJvZHVjdD1CTiZwaG9uZT0xKzgwMCs0MjUrMDIyJmxpbms9aHR0cCUzQSUyRiUyRnd3dy5ibHVlbmlsZS5jb20lMkZhdSUyRl9MRDA2MDkwNTgwJmN1cnJlbmN5PUFVRCZsYWI9Z2lhJnNrdT1MRDA2MDkwNTgwJg%3D%3D

Carat weight 1.00
Shape Round
Cut Ideal
Colour E
Clarity SI1
Length/width ratio 1.00
Depth % 61.6%
Table % 57.0%
Polish Excellent
Symmetry Excellent
Girdle Medium to Slightly Thick
Culet None
Fluorescence Medium
Measurements 6.37 x 6.39 x 3.93 mm
http://www.bluenile.com/certs/7218301710.pdf?params=Y291bnRyeT1BVVMmcHJvZHVjdD1CTiZwaG9uZT0xKzgwMCs0MjUrMDIyJmxpbms9aHR0cCUzQSUyRiUyRnd3dy5ibHVlbmlsZS5jb20lMkZhdSUyRl9MRDA2NTM0OTM5JmN1cnJlbmN5PUFVRCZsYWI9Z2lhJnNrdT1MRDA2NTM0OTM5Jg%3D%3D

Both are very similar in price and are reported as eye clean by BN. Any thoughts on what I should pick?
 

Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
SWell, your research needs some fine tuning.

First one is too deep. WAY WAY WAY too deep. ;)) Forgetaboutit.

SSecond one isn't pulling up for me. What are the crown pavilion angles? Run through the HCA please, and if it's under 2 then it's okay. But it's not facing up like a 1 carat. It's supposed to be facing up 6.5mm. https://www.pricescope.com/tools/hca

Are you sure you gave me the right numbers on these stones? And just an FYI we need crown and pavilion angles.

Is the Si1 eyeclean? Did you ask already? Blue Nile can tell you that.
 

Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
Read please:

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.
 

Typhon

Rough_Rock
Joined
Jan 30, 2016
Messages
5
Thanks for the responses. I've certainly been focusing on cut, and have run both through the HCA calculator which is why I thought they looked promising.

The 0.96 ct stone is 1.0

The 1.00 ct stone is 0.9

As previously stated, BN have advised both stones are eye clean according to their vault managers.

I'll look into the Idealscope too.
 

Gypsy

Super_Ideal_Rock
Joined
Aug 8, 2005
Messages
40,198
Then the second one is better.
 

gr8leo87

Shiny_Rock
Joined
Apr 24, 2015
Messages
381
Gypsy said:
SWell, your research needs some fine tuning.

First one is too deep. WAY WAY WAY too deep. ;)) Forgetaboutit.

SSecond one isn't pulling up for me. What are the crown pavilion angles? Run through the HCA please, and if it's under 2 then it's okay. But it's not facing up like a 1 carat. It's supposed to be facing up 6.5mm. https://www.pricescope.com/tools/hca

Are you sure you gave me the right numbers on these stones? And just an FYI we need crown and pavilion angles.

Is the Si1 eyeclean? Did you ask already? Blue Nile can tell you that.
Most of the ideal cuts especially the hearts and arrows range don't face up a full 6.5 mm for a 1.00 ct. More like 6.40 - 6.45.. Which is still pretty good for the light play they have.
 

FancyDiamond

Brilliant_Rock
Premium
Joined
Jun 16, 2009
Messages
1,035
In the case of the 0.96 ct stone, I would not place much faith on the HCA number, because the symmetry is not excellent. Not sure if the measurements were taken at representative places. Besides, I think the depth of 62.8% is too much.
 
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