New to diamonds, Question on measurements.

[chaininsomniac]

Just wondering, what range should I be looking for in table and depth for a .5-.65 ct. round cut, what about for princess?

 

[Lorelei]

Date: 12/19/2008 4:12:54 PM
Author:chaininsomniac
Just wondering, what range should I be looking for in table and depth for a .5-.65 ct. round cut, what about for princess?

Welcome!

For a round diamond of any size, a good set of proportions such as depth and table remain the same. Here are some numbers you can use as a guide to help you find a well cut round.

depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate.

And from expert John Pollard.

As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here's a "Cliff's Notes" for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

As for Princess, you can use this chart as a guide but don't get hung up on the numbers otherwise you could miss out on some diamonds which you might be very happy with.

http://diamonds.pricescope.com/fnc1.asp

It isn't really possible to judge a Princess by the numbers as all that will give you is a chalk outline, it is best to work with a vendor who has in house diamonds and can supply photos and ASET images in order for you to be able to choose a well cut Princess. If you want to narrow the field then you can consider AGS0 cut grade Princess which should be well cut diamonds, also the advice and experience of a trusted vendor is invaluable, especially if you are looking at GIA graded Princess. There are well cut Princess which have been graded by GIA but it can take more work to find them.

 

[beach]

A thread was started the other day that may be helpful. Here it is:
https://www.pricescope.com/community/threads/my-buying-guide-of-princess-cut-diamond-for-non-professional-first-time-buyers.102728/