Cut Question for non ACA diamond

[D2B]

Hi

I got a package from WF today, promise will show pictures later in the week in the show me your ring section. Now it came with a hearts and arrows viewer, as they are ACA studs. so I couldnt resist and used the viewer on my other rings. Now one stone in particular, is incredibly shiny, only .15 carat, and has this image. What is the white circle in the middle? What does it mean for sparkle etc. Like I said they look great, arnt ACA, but now I am curious what does this sort of pattern mean, if anything?

PS my camera is just so not up to the job, so appologies, but IRL it is a definate white circle in the middle. Most of the other stones have arrows, even though they are not ACA's.
Thanks for the info in advance and if there are any old threads on this, happy for someone to point me in the right direction.

D2B

edited to add: Yep, should have cleaned my rings, it is amazing how dirty your apparently sparkly ring looks in macro.

 

[arjunajane]

Hmm..I''m not that informed but am gonna take a stab..It looks like it is a "traditionally" faceted RB, and the white circle effect could be due to a smaller table size than you see in ideal cuts..?
Just a guess, I know it doesn''t really answer all your Q''s sorry!

ps. can''t wait to see photos of the WF goods!

 

[Ellen]

I''m thinking it may be leakeage (the dark ring) that is causing it. If you look at the diamond to the right, the center looks the same in the very middle, but there''s no dark ring around it, causing it to look like a "white spot".

That''s just a guess. Hopefully an expert will chime in to clarify.

 

[arjunajane]

Date: 5/27/2008 8:31:13 AM
Author: Ellen
I''m thinking it may be leakeage (the dark ring) that is causing it. If you look at the diamond to the right, the center looks the same in the very middle, but there''s no dark ring around it, causing it to look like a ''white spot''.

That''s just a guess. Hopefully an expert will chime in to clarify.

lol, I knew you could rely on Miss Ellen or one of the other smarties to chime in! (and show up my idea of course!

)

 

[Ellen]

Date: 5/27/2008 8:35:34 AM
Author: arjunajane
lol, I knew you could rely on Miss Ellen or one of the other smarties to chime in! (and show up my idea of course!

)

Hey, nobody said I''m right yet!

 

[John P]

You’re seeing table reflection. It is, literally, the reflection of the table seen in the pavilion of the diamond in various lighting conditions. Diamond cutters have used this phenomenon since before scanners ever existed to judge pavilion depth.

Here is a graphic showing how table reflection increases as table size (top) or pavilion depth (bottom) increase. Bear in mind these are "perfect" wireframe simulations. In real diamonds a level of asymmetry will 'bloat' the reflection's appearance, as you can see in the photo you provided.

At a glance I’d estimate the diamond in your photo is closer to 65T and 41.5PD (modeled below) than most of the combos we see here. Although not many are pictured on PS such makes are common commercially. We typically get small-tables here but in a global sense GIA considers 65% the lower end of the “large” table range (60-64% medium and 53-59% small).

Ellen, your leakage guess was close. The dark ring around the reflection is the obstruction pattern that comes with large table reflection. It's literally a reflection of the viewer's face (or camera in this case) on the outside of the whiteness the inner table reflection is returning, so it is not returning light in this position.

Great photo by the way D2B. And congrats on your purchase.

 

[arjunajane]

Date: 5/27/2008 8:44:08 AM
Author: Ellen

Date: 5/27/2008 8:35:34 AM
Author: arjunajane
lol, I knew you could rely on Miss Ellen or one of the other smarties to chime in! (and show up my idea of course!

)

Hey, nobody said I''m right yet!

lol, Yes, He did!!

But, I was kiinda close with summin to do with table, right..?

 

[D2B]

Thanks everyone
John it was great to read your response. So, is this an example of Fisheye?

D2B

 

[John P]

Date: 5/27/2008 9:15:35 AM
Author: D2B
Thanks everyone
John it was great to read your response. So, is this an example of Fisheye?

D2B

Happy to help. Actually a fisheye occurs when the pavilion depth is so shallow that you see the girdle reflection in the table as a whitish ring. Yours is on the deeper side of the line but it's not in the nailhead category. With a deeper pavilion the center would go dark in just about every condition you viewed it in.

Here is a GIA page with photo examples of fisheye and nailhead.

 

[Ellen]

Date: 5/27/2008 9:08:44 AM
Author: arjunajane

Date: 5/27/2008 8:44:08 AM
Author: Ellen

Date: 5/27/2008 8:35:34 AM
Author: arjunajane
lol, I knew you could rely on Miss Ellen or one of the other smarties to chime in! (and show up my idea of course!

)

Hey, nobody said I''m right yet!

lol, Yes, He did!!

But, I was kiinda close with summin to do with table, right..?

Nah, just close.

John, thanks for the informative post, we''ve missed those too.