Find your diamond
Find your jewelry
shape
carat
color
clarity

Why this ideal cut diamond earns a 2.7 HCA??

It's pretty deep, with high crown and pavilion angles that don't complement each other as well as ideal cut diamonds.
 
because its not an ideal cut its a gia ex cut and some of them are out of the normal ideal cut range.
With in the GIA rounding and depending on specifics that stone could get ags0 to ags2.
So it might be one of those edge case ideals and the hca wrong because of garbage data going in.
To override the hca more data would be needed like an IS/ASET image.
 
Karl_K said:
because its not an ideal cut its a gia ex cut and some of them are out of the normal ideal cut range.
With in the GIA rounding and depending on specifics that stone could get ags0 to ags2.
So it might be one of those edge case ideals and the hca wrong because of garbage data going in.
To override the hca more data would be needed like an IS/ASET image.
Click to expand...
 
The HCA tool is not going to tell you if a diamond is ideal or not. The HCA tool helps determine if the angles of the stone are complimentary once you have a GIA Ex or AGS Ideal in hand. The HCA is basically a coarse filter tool to narrow down the large number of GIA Ex or AGS Ideal that meet the below parameters into a smaller number than have complimentary angles. Then, you need to request a Idealscope image or ASET image to confirm performance and light return.

The second diamond you linked 3203514 is a different style of diamond. It is a 60/60 style diamond and will return more white light than fire.

Why don't you simply request an Idealscope (IS) or ASET on the diamond to be sure it is going to perform well? If your friend has the diamond in hand, you can buy your own IS. If JA has the diamond, ask them to send you a IS or ASET (usually they give IS) and post it here.

This is the kind of diamond most PSers would recommend...smaller table, lower crown angle. While this weighs slightly less, it is actually going to face-up a bit bigger than your friends by 0.03 mm. We'd still want to see an IS or ASET.
https://www.jamesallen.com/loose-diamonds/round-cut/1.03-carat-h-color-vs1-clarity-excellent-cut-sku-3475223

If budget allows, this is even better and the IS looks great:
https://www.jamesallen.com/loose-diamonds/round-cut/1.09-carat-h-color-vs2-clarity-excellent-cut-sku-2519524

Typical "ideal" parameters are below:
Table: 54-58
Depth: 60-62.3
Crown angle: 34-35.5
Pavilion angle: 40.6-42
 
Last edited:
Neither of those diamonds is in the range that usually will show a truly ideal cut diamond. Keep in mind that around 80% of GIA diamonds are graded Excellent for cut, so that grade absolutely does NOT indicate a stone is going to be ideal cut.


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 (up to 35.5 crown angle can sometimes work with a 40.6 pav angle)
pavilion angle: 40.6-40.9 (sometimes 41.0 if the crown angle is close to 34)

(@rockysalamander I think you have a typo on your pav angle numbers.)
 
diamondseeker2006 said:
Neither of those diamonds is in the range that usually will show a truly ideal cut diamond. Keep in mind that around 80% of GIA diamonds are graded Excellent for cut, so that grade absolutely does NOT indicate a stone is going to be ideal cut.


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 (up to 35.5 crown angle can sometimes work with a 40.6 pav angle)
pavilion angle: 40.6-40.9 (sometimes 41.0 if the crown angle is close to 34)

(@rockysalamander I think you have a typo on your pav angle numbers.)
Click to expand...
Yup. Typo. Thanks. Did you mean neither of OPs stones were witin ideal or the ones I posted?
 
The IS image for the https://www.jamesallen.com/mobile/l...h-color-vs2-clarity-excellent-cut-sku-3203514

3203514id.jpg

rockysalamander said:
The HCA tool is not going to tell you if a diamond is ideal or not. The HCA tool helps determine if the angles of the stone are complimentary once you have a GIA Ex or AGS Ideal in hand. The HCA is basically a coarse filter tool to narrow down the large number of GIA Ex or AGS Ideal that meet the below parameters into a smaller number than have complimentary angles. Then, you need to request a Idealscope image or ASET image to confirm performance and light return.

The second diamond you linked 3203514 is a different style of diamond. It is a 60/60 style diamond and will return more white light than fire.

Why don't you simply request an Idealscope (IS) or ASET on the diamond to be sure it is going to perform well? If your friend has the diamond in hand, you can buy your own IS. If JA has the diamond, ask them to send you a IS or ASET (usually they give IS) and post it here.

This is the kind of diamond most PSers would recommend...smaller table, lower crown angle. While this weighs slightly less, it is actually going to face-up a bit bigger than your friends by 0.03 mm. We'd still want to see an IS or ASET.
https://www.jamesallen.com/loose-diamonds/round-cut/1.03-carat-h-color-vs1-clarity-excellent-cut-sku-3475223

If budget allows, this is even better and the IS looks great:
https://www.jamesallen.com/loose-diamonds/round-cut/1.09-carat-h-color-vs2-clarity-excellent-cut-sku-2519524

Typical "ideal" parameters are below:
Table: 54-58
Depth: 60-62.3
Crown angle: 34-35.5
Pavilion angle: 40.6-42
Click to expand...

Karl_K said:
because its not an ideal cut its a gia ex cut and some of them are out of the normal ideal cut range.
With in the GIA rounding and depending on specifics that stone could get ags0 to ags2.
So it might be one of those edge case ideals and the hca wrong because of garbage data going in.
To override the hca more data would be needed like an IS/ASET image.
Click to expand...
 
Here's an example of a GIA Ex cut idealscope image that would be within the ideal cut range.

1.65 G VS1 (AGS) idealscope.jpg
 
You must log in or register to reply here.
GET 3 FREE HCA RESULTS JOIN THE FORUM. ASK FOR HELP
Jewelry Blog
PriceScope-Concierge-Ad
Find prime cuts.
Top