Answer: There was a time when GIA courses promoted the concept of "ideal proportions". Since then, with the technological developments and advancements that allowed more exact testing of cut diamonds in the area of brilliance and "fire", it was determined that in reality the proportion parameters that yielded an appealing diamond are not as narrow or as limited as was once believed. But rather there exists a larger range of proportioning combinations that results in an attractive and desirable diamond. This change in thinking also takes into consideration that people in general have different tastes and preferences and if shown a number of diamonds cut with various proportion combinations that display high degrees of brilliancy and fire that there would be varying opinions of which of them is the most beautiful. The term "ideal" cut denotes exact specifications, which is not realistic since there is no single set of proportions that creates a beautiful diamond, so under the circumstances "ideal" is not a fitting term. And in this sense the term "ideal" becomes more subjective. Articles on the topic of diamond cut have been published in the Fall 1998 , Fall 2001, and Fall 2004 issues of GIA's quarterly publication of Gems & Gemology. The first two articles are available on our website.  These Gems & Gemology issues may be purchased online, or by contacting Subscription Services, GIA California, at (800) 421-7250, ext. 7142 or e-mail: dortiz@gia.edu.

Also on the GIA website, under the heading GIA Research, you will find a series of short articles, called "GIA on Diamond Cut", that explain the basis of our cut research and discuss key issues in the evaluation of proportions for round brilliant cut diamonds.

A list of scientific and technical FAQs is now available in the GIA on Diamond Cut section of GIA's website, and will be updated periodically as needed. To view the FAQs, click here

This extensive research has been used to develop a cut grading system for round brilliant diamonds that will be incorporated into GIA's diamond training in education and into diamond grading in the laboratory in 2005.