Ideal proportions of a Round Brilliant

[daskeg]

Pretty simple question here regarding Round Brilliant cut diamonds

Is there an ideal proportion that I should be working off.

I've read heaps about the anatomy of a diamond on this website, but i didn't come across anything that specifically says, this is the ideal proportions for a Round Brilliant Cut diamond.

 

[dmdshopper]

Search the forum for 'angles' and you should come up with a bunch of hits

In my amateur reply I think most people will direct you to the Tolkowsky angles below:

depth - 60 - 62%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees

However, i've seen 60/60 (near 60% depth and 60% table) that looked stunning in person too (compared side by side to a Hearts on Fire)
Ultimately you need to see some in person and decide for yourself what you like.

 

[diamondseeker2006]

There are diamonds outside of those parameters that are nice, but they are a good starting point. Stick with GIA Excellent Cut (or if you look at AGS Ideal cut, they have already evaluated light performance and those are generally great stones).

Add...girdle: thin, medium, slightly thick

 

[daskeg]

Thanks dmdshopper. That explains why my search results weren't coming up with the right links.

Yeah I do intend to view in person but the guy who im working with can usually only bring 3 stones to look at each time. So if I can have a better understanding of what i'm looking at in terms of "angles" I can make a better decision, rather than just blindly trusting what someone tells me.

 

[DiamondBrokersofFlorida]

If you go with an AGS graded ideal cut diamond you should be good to go on most of the angles and percentages. I tend to like to keep the depth 62% or under so that you have a better size look for the weight. I especially like the platinum reports with light performance on them too.

 

[Christina...]

Totally agree, limiting yourself to AGS0 stones, takes a lot of guess work out of finding a nice diamond. You're probably good with GIA Excellent as well, but they have a wider range of excellent cut, some feel it's too wide. So, you should do some further investigating, HCA, Ideal scope, magnified images and such.

This may help..https://www.pricescope.com/wiki/diamonds/diamond-grading-chart-round