Academic Query - Girdles & Light (revisited)

[Cehrabehra]

I know this was a great topic of discussion 5 years ago, quite a few times - and of course I can't find any of them in a search.

The reason I bring this up is that I bought a ring with 3 ideal cut rounds that are set in kind of a channel setting and they are just not as brilliant as my poorly cut mall bought earrings that are in a traditional 4 prong. They do have more fire but they seem darker. I'm going to get my cushion cut reset soon and it occurs to me that I should brush up on the affect of blocking light from entering the girdle before I make a final decision on a setting.

I know that bezel settings have been really popular lately, but pictures of stones in them just don't glow the way stones do in settings that let light in the girdle. And I know it isn't *supposed* to matter, light from the top and all that... but not every diamond we love is a super-ideal.

So one more time, what impact does light from the girdle play... and if you want to go further, what impact does light from the pavilion play?

 

[Cehrabehra]

Wow, ps has certainly changed over the years. A few years ago this might have been the most popular thread and now there is no one to answer it?

 

[MichelleCarmen]

I notice with my diamonds that plenty of light is thrown off from the girdle and little rainbows come out from the side...on my bezel pendant, the girdle is covered so there is less exposed diamond for there to display light return, so less color flashes are present. When you tilt your diamonds around, there should be color seen from as many angles as possible, so *to me* I would want to provide all opportunities for that to happen and I think a bezel limits that.

 

[kenny]

I'll bite . . . and chew a bit.

It has been argued that "well cut" means all light entering the top gets returned back out the top, rather than leak out the side or bottom. (Okay, maybe not 100% of the light, but as much as possible. For purposes of the hypothetical below let's ignore desirable contrast leakage.)

I have a round Solasfera.
This cut has 100% light return as demonstrated by its solid blood-red Idealscope performance.

Other cuts like Eightstar and the former "new line ACA" also achieve this no-leakage performance.

My Solasfera is in a tension setting which lets light in (and out) via the top, sides and bottom so it is a great guinea pig for a discussion on how settings affect what you see from diamonds with various levels of light performance/leakage.

I can testify that even this diamond with "perfect" light return (out the top) gives off TONS of flashes of colored fire and light from the pavilion.

Humor me here.
Imagine two rooms separated by a wall with tiny hole.
In that hole is mounted a Solasfera diamond.
Imagine you were in a dark room on the diamond's pavilion side.
Imagine the room that the crown faces has a lot of light.
Since this diamond returns all of the light entering the crown back out the crown it stands to reason that you, being in the pavilion room, would see no light.

Since I see tons of light flashes coming from the pavilion of my Solasfera I can only surmise that those particular light rays did not enter the diamond via the crown.
They had to enter the diamond via the pavilion side.
Entering at the girdle itself is possible but the girdle many diamonds have girdles so thin as to be a relatively insignificant window compared to crown and pavilion facets.
Even the thick girdle of an asscher is only around 3% . . . meaning 97% of your side view will be crown or pavilion facets.
Hence the actual light flashes coming from the girdle itself are not significant.

Sara, to get back to your original question, yes bezel settings stop light from getting into and out of more of the diamond than other settings.
Whether the diamond is well-cut or not it stands to reason that bezel settings reduce the bling.
Keep in mind diamond cut may be judge by top-view only, but we usually see them in a side view.

IMHO a tension setting such as the one our Octavia lives in, below, will make ALL diamonds, well-cut or leaky, look their brightest.

 

[Rhino]

Hi Cehrabehra,

Good question. In essense girdle thickness, while impacting the cut grade of a diamond will not and does not impact the optics.

The girdle is positioned in such a way that it is drawing light strictly off the horizon and at very low angles. The only time it really impacts optical properties is when you can see its reflection under the table (ie. fisheye effect).

With regards to ideal cut diamonds looking dark, this is a subject that's been discussed on the forum quite a few times and is something I tackle more specifically in a video I did on the subject of diamond color (ie. What Diamond Color Isn't).

Now ... one positive aspect of leaky diamonds is that it will cause them to be lighter in appearance in the same lighting that ideal cut diamonds go dark in albeit they will lack the fire and sparkle of their ideal counter parts which you justlly point out.

With regards to setting your cushion, a bezel covering your girdle will not impact its appearance as much as blocking the pavilion will and why perhaps many of the pix you see in bezels aren't as glowing. It would be the blocking of the pavilion as opposted to blocking the girdle that causes what you are seeing.

Hope that helps dear.

Kind regards,
Rhino

 

[Cehrabehra]

Thanks guys!

Kenny, I totally can follow your logic, it makes sense. More on that later...

Jonathan, I don't see how you can say that it never affects optics... I mean if you're at sunrise or sunset and the diamond is held at a 90* angle to the horizon, it's going to enter the girdle and create some magic, no?

I guess I also kinda confused things by mixing up girdles and pavilions into one discussion, but they're both relevant to me.

When my diamond was just held in the little temp holder dohicky thing it was a rockstar. IIRC there is a lot of metal covering the sides of the pavilion so that can't be what is holding my stone back. It must have something to do with light *under* the diamond more directly not just from the side.

All I know is that my stone needs to be in the right place because all of this superior light performance stuff be damned, I have never seen a prettier stone than mine twinkling colors from *everywhere. It's somehow better in its flaws (in my eyes) than any of the well cut stones. It does things the others do not - it takes light from the pavilion and pushes it out.
In this pic I am not wearing a pink shirt - no idea where the pink came from. You can see green from the trees, blue from the sky, flesh colors from my skin, black from the camera. It would just soak up the color from every direction and create a kaleidoscope. I loved that! I apologize for going off topic here in my own academic query, but I *still after how many years here do not understand why everyone is so hung up on the light from above only way of thinking. I get that it is good for internet sales, but I may never understand why more flavors aren't embraced. I used to love talking with diagem about this stuff. He totally understood seeing a diamond as a 3D sculpture not just a face down thing. Maybe he's changed his opinion on that... I don't even know where I'm going anymore with this. I will come back to this once my head stops spinning.