« Gem of A Bridal Gown! Most Expensive In U.S. | Main | Winter Olympics Slows Jewelry Buying on the Net. »
GIA Cut Grade for Round Brilliant Shape Defined.
The GIA (Gemological Institute of America) the worlds foremost diamond grading laboratory introduced their new Cut Grade system for round diamonds on January 1, 2006. This new cut grade system is based on 15 years of intensive research which included sophisticated computer modeling and over 70,000 human observations of diamonds differing in cut quality and measurements.
The new Cut grades are divided into the following categories:
Excellent
Very Good
Good
Fair
Poor
99% of the diamonds graded by the GIA will fall into one of the top three categories.
On March 10, 2006 Tom Moses issued a release further defining the parameters of the new GIA Cut Grade. I have reprinted his comments in their entirety below in order to give you consumers a better understanding of this new Cut Grade system and how it may help you in your purchasing decisions.
From the GIA website, 3/10/06.
March 10, 2006
From the GIA Laboratory: Six Defining Qualities of the New GIA Diamond Cut Grading System
"With the announcement and subsequent launch of the GIA Diamond Cut Grading System, I am frequently asked to explain the benefits of our system. Over the last several months, we have tried to address this and other aspects of the new cut grading system during the many presentations we have given on it, both domestically and internationally. At this time, I would like to share some of what we have presented.
The defining qualities of the GIA Diamond Cut Grading System are:
1. The system is Scientific. It rests on a foundation of peer-reviewed research, which included computer-modeled light behavior and statistical analysis of observations by members from all sectors of the international diamond community. Rather than starting with preconceived notions of which proportions and other factors lead to beauty and high cut quality in round brilliants, we used custom-designed computer ray-tracing and extensive observation testing to explore broad areas of proportion space. During the course of this methodical process, we scientifically proved what many in the industry had long felt about good proportions in round brilliants, but also discovered areas of proportion space that many in the trade never suspected could produce quality diamonds.
2. The system is Practical to use. It is visually intuitive—attractive diamonds receive favorable grades and unattractive diamonds are described as such. We also carefully considered what the “right number” of grades should be in a practical system—and arrived at five (excellent, very good, good, fair, and poor) based on the limitations of visual discrimination. The visual basis of the system also allows it to be taught (and learned) easily in our Education courses, and experienced members of the diamond trade can quickly see that GIA cut grades make sense and are easily understood.
3. The system is Comprehensive. Face-up appearance may be the most important part of a diamond cut grading system, but it is not the only part that should be considered. Our new system also includes aspects of physical design (such as weight and durability) and craftsmanship. All of these factors are considered in the determination of a final, overall cut grade.
4. The system acknowledges personal and regional Tastes and Preferences. One of the most compeling findings from our observation tests and interviews was that different people prefer different appearances in diamonds. Sometimes these differences are from one person to another, and other times they represent preferences in certain countries or regions. We knew that the GIA Diamond Cut Grading System had to be applicable around the world. In some cases, this meant recognizing that a certain face-up appearance might be favored by some but not others. This recognition, backed by the findings of our ray-tracing and observation tests, is incorporated into the final system. Even though there can be different appearances within a given GIA cut grade (a good thing from both a sales and consumer point of view), the overall performance (e.g., the brightness and fire) of each diamond with the same grade is similar.
5. The system is Predictive. Manufacturers, whether polishing a diamond from rough or recutting a polished diamond for a better grade, need to know before they start what cut grade they can expect from a certain set of proportions. The GIA Diamond Cut Grading System allows them to do this by using any of the GIA Facetware™ products—the free online Facetware Cut Estimator and Facetware Look-Up Tables, or the Facetware Database as embedded in non-contact measurement devices (such as those offered by Sarin and OGI).
6. Last, but certainly not least, the system is Accessible. Consistent with GIA’s status as a public benefit corporation, we have made the system available to anyone who wants to use it. To this end, we have developed software (GIA Facetware) that predicts cut grades and is available in several different formats, as described above. We have also dedicated a whole section of our website to presenting relevant information about the GIA Diamond Cut Grading System. In addition, since we announced the system in August of 2005, representatives of GIA Research and the Laboratory have been offering presentations at trade shows and in major cutting centers in the United States and internationally. Starting in January, GIA Education began teaching students how to use the new cut system in half-day seminars, and it now includes this instruction in all new diamond-related course material. Everything needed to use and understand the new cut grading system is readily available.
We are confident that we have created a diamond cut grading system for round brilliants that is accurate, complete, and practical. It is a system that can be used and understood by the public to make informed buying decisions, and by manufacturers to maximize the beauty from rough. For more information about the new system, please visit our diamond cut microsite. www.gia.edu
Thank you,"
Tom Moses
Senior Vice President, GIA Laboratory and Research
Comments
i dead you report but because my english is very bad ,i want to ask you to write this report in french and i will give you my point of view .i'm a sorter of diamond there are now 25 years ago to cso and work now for miba company like controler sorter. please i want to be in contact with you conpany about every things tellin diamonds
thanks .
Posted by: kavula on September 21, 2006 8:12 AM
i read a article that new GIA cut grading system started in Jan./2006, means that the conventional cut system which was just as Tolkowsky cut(Ideal cut), denied and abolished by GIA or? i would like to ask you why GIA laboratory abolished Ideal cut for what? i want to know the truth.
Posted by: Misuzu Hayashi on January 24, 2008 1:53 AM