Which diamond would you choose?

[diamondhelp123]

Price does matter as I am working with a budget but I've found two stones I like on Blue Nile. One is higher graded, but seems to have lots of feathers which from reading here doesn't seem great. They have told me the SI2 is eye clean. Which would you choose?

http://www.bluenile.com/diamond-details/LD05101512

http://www.bluenile.com/diamond-details/LD05221966

Many thanks!

 

[HopeDream]

Hi Diamond Help123,

Both stones are only so-so. The lack of pictures of them is a huge problem, because you can't see how the inclusions change the character of the stone. # 1 scores 2.4 on the HCA, #2 scores 2.5, so, not the best in terms of sparkle or fire.

Here are some top performers in your budget which are a tiny bit smaller (6.2mm vs 6.6mm), but will sparkle much more than a larger, duller stone:
All are eye-clean, so you won't have to worry about seeing inclusions.
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3114501.htm?source=pricescope
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3273924.htm?source=pricescope
http://www.whiteflash.com/loose-diamonds/round-cut-loose-diamond-3034520.htm?source=pricescope

 

[Gypsy]

Here is 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. 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 62.5
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.


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.

 

[HopeDream]

If you're going by Gypsy's advise to just stick to AGS 0,
Then this probably the biggest stone with top light performance in your budget:
http://www.eternitybyyoni.com/diamond_detail.php?id=1580599&ref=pricescope

Don't know what it looks like though.

 

[Darkman]

(Great post, Gypsy, lots of background - thanks!)

 

[diamondhelp123]

thanks so much for all your help and advice. The HCA calculator sure is interesting as I definitely want sparkle! I have a ring now I hate b/c it doesn't shine like it should and I see when I look at it is dullness.

I'm used to H color diamonds, but due to price looking at I or J. Is an internally flawless J better than a SI1 or VS2 I? Will the color difference be slight if the J is cut better? Both the I SI1 and VS2 are 1.3 on the HCA. I've seen so many threads on here with J diamonds that look so white just worried about dropping two colors whereas I think down to an I wouldn't be as noticeable.