Class II cut

[buzzf]

The book "How to Buy a Diamond" says that anything greater than 61% total depth is a class III cut. If it is over 61%, something is wrong with the crown or pavilion angle. Do you agree?

 

[strmrdr]

no
some of the most awesome round diamonds iv ever seen had a depth between 61 and 62.

 

[denverappraiser]

The cut grading criteria used in that particular book are not very widely accepted but I think you are correct that he does not recommend buying stones of over 61% depth. No, I don’t agree with this advice.

Neil Beaty
GG(GIA) ISA NAJA
Professional Appraisals in Denver

 

[brum]

The topic of ideals is some what confusing, there are so many points-of-view on what is a class 1 cut.

I''m just about to purchase a diamond on-line.

Whilst appreciating that certain angles can be class 1, but may not be suitable for other facet angles which also fall into the class 1 bracket, What do you pro''s believe are the rights specs for class 1 or the best ideal cuts?

Cheers

 

[denverappraiser]

Cut grading of diamonds, especially round brilliant cut diamonds, is a subject of great interest here. You’ll find it discussed at great length in both the tutorials at the top of the page and previous posts in this forum. As you point out, not everyone uses the terms the same way and it causes a fair amount of confusion. A class I- II – III system was used by GIA a few decades ago but wasn’t really specific enough to prove to be useful. It was was subdivided by AGA into Ia, Ib, etc. and the AGA system enjoyed, and continues to enjoy fairly broad acceptance. It’s explained nicely at www.gemappraisers.com under the DIY cut grading section. Buzzf's book has it’s own system using similar terms that I think are explained in the book. There is a brand new system from GIA that is being hotly debated and can be viewed at www.facetware.gia.edu that grades stones on a 5 step scale from poor to excellent. AGS grades stones from 0 –11 and AGS-0 is a popularly used definition of ‘ideal’ although they changed this definition last year so really there is a pre-2005 AGA and the current AGS approach.

What’s a customer to do?

Start in the tutorials at the top of the page. Read the sections on cut grading in their entirety. Then hit the forum and start reading what people have had to say about it. You can narrow down things with the search box as you find topics of interest. There’s good material in the FAQ section of the forum and there’s a section called the ‘journal’ that contains some articles that may interest you. There are several dealers who maintain free strong educational content on their own sites are all contain a link at the bottom of their posts. If you see a post from someone who seems to have good information, follow the link in their signature and see what they have on their own website. Read thoroughly the educational content of the site you are planning on buying from. This should give you a good idea where they stand on the various issues, not everyone agrees about what’s best.
It’s not as daunting as it sounds. It’s a narrow topic in gemology and a few evenings of study can result in a remarkably good education.

Happy hunting.

Neil Beaty
GG(GIA) ISA NAJA
Professional Appraisals in Denver

 

[Hansel]

If you are buying online, check out DiamondsRight.com. I am getting my band there for super cheap: Platinum 950pt. 2mm band for $315. They are unbeatable for bands online and their diamonds were only slightly more expensive than my family friend who said he was making very little profit off of my stone.