Putting it all together

[steppapajon]

First of all thank you to everyone that makes this site possible. I have spent a lot of time learning from the wonderful posts here.
I have also spent a lot of time looking at a very large variety of diamonds on the James Allen site. The videos help me compare my likes and dislikes. I am very surprised at what I found. I like diamonds with a pavilion depth of 14% or less. I also like a larger table.
And most of the time the diamonds I like are not making the 2.0 cut with HCA. My question to you all is this. What do I "like" that by all accounts should be "wrong". I know personal taste is a factor but I am beginning to question mine.
James Allen SKU: 285490 is an example. Look pass the inclusions, and the price and size are irrelevant. There is something about it that I really like. More so as it turns away from the viewer. Can someone tell me what that is?
Thank you,
SPJ

 

[diamondseeker2006]

You're going to need to paste the link to the diamond for us, please. I put that number in their search and it didn't come up.

The key is, you don't want a diamond with a lot of leakage. You want it to have great light return whether you prefer more of a 60/60 stone or a Towlkowsky ideal cut. So I have not idea of the stone you are looking at, but you need to be looking at proportions that will keep you in ideal cut territory. You can weed them out with the HCA and consider stones that have a score of maybe 2.5 or lower, and then request the idealscope images to be sure there isn't leakage.

 

[diamondseeker2006]

One more thing, these highly magnified images are great to see the cut of the stone, color, and clarity. But you can't really use them for determining preferences for performance because you have to see them in person in various lighting to decide that. They look a lot different in real life! That is why we generally recommend sticking with ideal cut stones when ordering stones that have not been seen in person and evaluated for light return.

 

[steppapajon]

Thank you for the response here is the link.
http://www.jamesallen.com/loose-diamonds/round-cut/0.90-carat-g-color-si1-clarity-excellent-cut-sku-285490

as to the keeping to proportions would a stone like this count or does the table size disqualify it? It is a 2.3 on the HCA
Measurements 6.26 - 6.29 x 3.78 mm
Carat Weight 0.92 carat
Color Grade G
Clarity Grade SI1
Cut Grade Excellent
PROPORTIONS

Depth 60.2 %
Table 61 %
Crown Angle 34.5°
Crown Height 13.5%
Pavilion Angle 40.8°
Pavilion Depth 43.0%
Star Length 50%
Lower Half 80%
Girdle Medium to Slightly Thick, Faceted, 4.0%
Culet None

 

[teobdl]

The JA stone: Pavilion angle is much, much too steep, and the crown is steep as well. What's catching your eye, probably, is the colored flashes, or "fire". Diamonds with steep pav/crown angles tend to reflect and refract light rays that our eyes perceive as color. Old European Cut diamonds have pav/crown angles similar to that, and they emit more colored light, whereas ideal modern round brilliants tend to have more of a balance of white and colored flashes.

The other diamond you listed has nice specs except for the table, which is huge. Thats why it's getting the lower HCA score. You can definitely find a better cut diamond than those you've listed. Is your price max $5,000?

try this diamond http://www.jamesallen.com/loose-diamonds/round-cut/0.91-carat-h-color-si1-clarity-excellent-cut-sku-281366

 

[ecf8503]

Thank you for the response here is the link.
http://www.jamesallen.com/loose-diamonds/round-cut/0.90-carat-g-color-si1-clarity-excellent-cut-sku-285490

as to the keeping to proportions would a stone like this count or does the table size disqualify it? It is a 2.3 on the HCA
Measurements 6.26 - 6.29 x 3.78 mm
Carat Weight 0.92 carat
Color Grade G
Clarity Grade SI1
Cut Grade Excellent
PROPORTIONS

Depth 60.2 %
Table 61 %
Crown Angle 34.5°
Crown Height 13.5%
Pavilion Angle 40.8°
Pavilion Depth 43.0%
Star Length 50%
Lower Half 80%
Girdle Medium to Slightly Thick, Faceted, 4.0%
Culet None

The link is not the stone you have listed specs for. Or are you asking about 2 different stones? The specs listed are ok for that stone, the linked one not so much. The linked stone scores a terrible 5.6 on the HCA!

Sounds like you like 60/60 stones. That's ok - just get an idealscope image to assess light performance. You can choose up to 3 stones, and they'll also have a gemologist's opinion.

 

[steppapajon]

The JA stone: Pavilion angle is much, much too steep, and the crown is steep as well. What's catching your eye, probably, is the colored flashes, or "fire".

That is exactly what i am drawn to.
My budget is pretty firm @ 4800-5200.
What is the down side to a "huge" table if the other proportions are ok? I am trying to understand how the table width affects the crown and pavilion angles. That part hasn't clicked for me.

 

[teobdl]

It's kind of hard to describe without an image. Briefly, given the same carat weight and same girdle diameter, a smaller table would make crown angle more shallow and pavilion angle more steep. But I don't think that's really relevant.

What's important is that there are specific angles and dimensions of a diamond that maximize our perception of them being pretty. We like when light rays enters from above, get bounced around inside the diamond, and then leave the the top of the diamond (not leaking out the bottom) and hit the eye to make nice patterns of white light, dark, and color. As the diamond moves, the patterns change dynamically, and it looks almost magical in a well cut diamond, like it is its own source of light.

ETA: The steep-deep may be very pleasing to your eye. It just happens to be different than the preference of most people. Also, beware that some light is probably leaking out of the bottom or side of the diamond--that's why we get these reflector images like IdealScope and ASET--so we can see the pattern of how things are reflecting back at us.

If you're into the physics of it, this AGS article is quite good http://www.agslab.com/spie/spie_lo_res.pdf

 

[steppapajon]

I will be sure to get an IS or ASET when I find something I think I like Teobdl. And the link you provided was a great read, well worth saving to read again.