Diamond proportions

[JackSpider]

Hi Guys,

I have shortlisted 2 diamonds based on TRIPLE EX and proportions.

Do you think these at least made the first cut and are worth pursuing further?



Thanks!

 

[Gypsy]

Not the first one. It's way too deep.

Run the second one through the HCA.

Here's what you need to know:

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 62.3. 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.

 

[JackSpider]

Hello!

I managed to get the video and images for diamond 1.

Could someone help me take a look, please.

I was told that its eyeclean even though its Si2.

VIDEO: https://vid.me/tjyd
http://pasteboard.co/1pfL9Oza.jpg
http://pasteboard.co/1pfNEua7.jpg

 

[JackSpider]

Sorry i realise i posted the wrong specifications for the 1st Diamond

it should be:



HCA score is less than 2

VIDEO: https://vid.me/tjyd
http://pasteboard.co/1pfL9Oza.jpg
http://pasteboard.co/1pfNEua7.jpg

Appreciate if someone could review this please

Thanks!

 

[Gypsy]

I would be wary of an SI2 with a grade setting cloud as it is likely to impede performance. Also those far away videos don't tell you much about the inclusions and thata the biggest issue.

 

[diamondseeker2006]

I also would avoid SI2, and if this is for an engagement ring, I would go no lower than J color.

These are measurements to help you stay in ideal cut territory with a GIA excellent cut stone.

table: 54-58

depth: 60-62.3

crown angle: 34-35.0

pavilion angle: 40.6-40.9 (sometimes 41.0 if crown angle is closer to 34))

 

[Gypsy]

If eyeclean, this one is nice:
http://www.b2cjewels.com/dd-7903064-0.91-carat-Round-diamond-K-color-SI1-Clarity.aspx?sku=7903064&utm_source=pricescope.com&utm_medium=referral&utm_campaign=pricescope.com

If eyeclean: http://www.b2cjewels.com/dd-8012646-1.01-carat-Round-diamond-K-color-SI1-Clarity.aspx?sku=8012646&utm_source=pricescope.com&utm_medium=referral&utm_campaign=pricescope.com

http://www.jamesallen.com/loose-diamonds/round-cut/0.90-carat-j-color-si1-clarity-excellent-cut-sku-803508 That's nice .

Also has potential: http://www.b2cjewels.com/dd-7399198-1.01-carat-Round-diamond-K-color-SI1-Clarity.aspx?sku=7399198&utm_source=pricescope.com&utm_medium=referral&utm_campaign=pricescope.com

 

[Gypsy]

Other options:
https://enchanteddiamonds.com/diamonds/view/Round/GIA-Certified-0-9-Carat-K-Color-VS2-Clarity-Diamond-5YRZFQ