Depth opinions

[me1234]

Could someone give me some general guidelines for what to look for in a diamond''s depth? Are diamond cut deeper than 61 ever worth looking at in thwe 2ct range? If so, what table and pav. angle would you need to result in a well-cut stone? Should I try to focus on depths below 60?

 

[me1234]

I am referring to rounds, sorry.

 

[Rank Amateur]

I think there are combinations in the 61+ range that still do well by eye and by HCA. In those upper carat ranges the cutters have even more incentive ($$/ct) to make 'em a bit on the deep side.

I'd say not to throw the baby out with the bathwater and look at each stone as it comes.

R/A

 

[hoorray]

David Atlas has a DIY cut grader along with a useful table of the parameter ranges that define different grades of cuts, on his web site: http://www.gemappraisers.com/ under DIY Cut Grader. It should help you decide the ranges for the different parameters that are in the category of quality you are interested in. Also, the HCA cut adviser on this site can help you evaluate the whole cut (how the different parameters work together), when you have all the different measurements for a stone.

 

[Richard Sherwood]

There are "deeper" stones which perform well optically. Note the AGA 1A category extends up to 62.99', the 2A category extends up to 63' and the 2B category extends up to 63.5'. Sometimes stones even deeper than that will look good to the eye.

The only problem with deeper stones is that as the depth increases, the diameter decreases. If the seller hasn't taken this into account and given the stone an appropriate discount, sometimes you'll end up paying for carat weight which you can't see with the eye. A 2ct for example with a 62.5% depth has the diameter that an ideal cut 1.85 ct would have.

It's not so much what the pavilion angle is that determines light return performance, but the relationship between the pavilion and crown angle. You could have two 41' pavilion angle stones with one performing magnificently, and the other one a dog.

It's like having the mirrors arranged correctly in a telescope. If they're spot on, the image is clear and crisp. If they're out of alignment, the image is muddy and blurred.

That's what the HCA is good at determining. Crown and pavilion angle combinations which perform well together. An IdealScope is good at that as well. Also, there's several contributors on here that have the DiamCalc software. They could tell you if you're looking at a potential pumpkin or a Cinderella.

 

[me1234]

Thanks for the info Rich, very helpful. In another one of my posts, you showed some pictures of dimensions that I was looking at. Were those from DiamCalc software?