Quick Question on 2 H&A

[MarionC]

I'm sure this has been done to death on this forum, but I couldn't find the answer.
Is one of these better than the other? I"m trying to learn to read the images.
The one on the left has an HCA of 2 and the one on the right has an HCA of 1.1.
Thanks.

 

[krisjon]

The first one has a bit of light leakage under the table (slightly white areas starting at 9 o'clock). Can you post the proportions for this stone? The second stone has the better IdealScope.

 

[yssie]

I'm sure this has been done to death on this forum, but I couldn't find the answer.
Is one of these better than the other? I"m trying to learn to read the images.
The one on the left has an HCA of 2 and the one on the right has an HCA of 1.1.
Thanks.

They're both about as good as ISs get

The one on the left shows what might on first glance look like "leakage" (light escaping out the bottom rather than being returned face-up back to your eyes), but the asymmetry of the star pattern under the table (the table reflection circle, etc.) indicates that the stone was slightly tilted relative to the scope during photography. Get that stone's girdle plane perfectly perpendicular to the scope and that "leakage" will disappear.

It's also important to remember that the scope has only one eye, whereas people usually have two, which work together to minimise this sort of leakage artifact. Slight "leakage" you might note under the scope won't be nearly as clear when you're looking at it IRL, even if you're specifically looking for it.

 

[krisjon]

Great explanation, Yssie.

I was just curious if maybe the depth/proportions on the first stone with 2.0 HCA were more on the edge of being optimal - hence the chance for the slightest touch of leakage. Both are great, though and the image angle makes total sense.

 

[yssie]

Great explanation, Yssie.

I was just curious if maybe the depth/proportions on the first stone with 2.0 HCA were more on the edge of being optimal - hence the chance for the slightest touch of leakage. Both are great, though and the image angle makes total sense.

I would agree that that's usually what HCA winds up representing IRL, yeah - how much you have to tilt it before you start seeing some sort of unwanted artifact, whether that's "leakage" or "girdle reflection" (fish-eye)... the ones you want to avoid are the ones that you don't have to tilt at all to see them! You can see in those two IS pics that the stones are very similar, but the table reflection on the one on the L looks slightly larger for the table size? So I assume pavilion angle is slightly deeper.

 

[MarionC]

Thanks! - very informative to hear you both discuss this.

On the left: 5.41x5.44-3.34
crown angle - 34.5
pavillion angle-41.0
depth-61.2
table-56

On the right: 5.58x5.60-3.39
crown angle- 34.0
pavillion angle-40.8
depth-60.60
table-58

 

[Dancing Fire]

any pics of the hearts? b/c they don't look like true H&A stones.

 

[MarionC]

any pics of the hearts? b/c they don't look like true H&A stones.