P.O. Box 620801

Woodside, CA 94062

650-739-8837

Ideal Cut Diamonds

Depending on who you are speaking with, an "ideal cut" diamond can mean many different things.

Originally, the ideal cut diamond was called a Tolkowski cut. Mr. Tolkowski had been assigned by the diamond company he worked for to find out what the "ideal cut" was. He started his thesis by setting out hundreds of diamonds on the sidewalk in London (in 1919) and asked passerby's which diamond they preferred. He also did many mathematical calculations regarding a diamond's brilliance.

From his research he developed the following formula: (chart)

As you can see it called for a 53% table and a depth of 59.3% plus the girdle (the outside edge of the diamond).

Several years ago Larzar-Kaplan brought this cut to the American public but it did not sell for two reasons. 1. The stone was very high priced, and 2. (and most important) it reminded people too much of an Old European cut diamond (the table was too small).

Lazar-Kaplan then got together with GIA and they came up with the new "American Ideal Cut". This diamond called for a 53%-57% table with the same depth. That ideal cut is still the varied combinations used today. 

The AGS (American Gem Society) contacted GIA also years ago and asked them if they could start grading their cut as AGS does, 0,1,2, etc.  GIA has done testing of a 53% table compared to a 59% table and by their own conclusion a 59% table can produce a more brilliant gemstone when pavilion proportions, etc. are altered to match. GIA is still trying to determine the grading of cut. 

If we were in Europe, a 60% or more table would be preferred.

With all this in mind, it would seem very important to look at as many varied combinations of cuts as you can. I personally feel a diamond that has around a 60%-62.5% depth and around a 55%-60% table, if the crown and pavilion angles are properly adjusted, can produce a very lovely gemstone that will rival many "Ideal cut" diamonds. But that is a judgment you should make for yourselves. 

When looking at a diamond, be sure to look at the diamond itself, and not its certificate paper.  I see customers bringing in "Certs" and asking me how much I would sell the same diamond for.  Without a diamond, however, a "Cert" is worth about ten cents. 

.

Robert Hilton

Third Generation Jewelry Designer

By Appointment Only