The following article was produced in collaboration with the AGSL. Special thanks to Alethea Inns, Director of Diamond Grading, for her invaluable help.
In keeping with their mission of consumer protection and education the American Gem Society Laboratories (AGSL) has just released a software program for evaluating cutting precision of the standard round brilliant diamond. And they have made this Visual Proportion Analyzer (VPA) software
available to the public for free!
The VPA is the same software used by AGSL to assess certain aspects of diamond cut quality. It analyzes aspects of faceting related to diamond cutting precision. With the VPA it is possible to easily gain sophisticated insights into the quality of diamond cut craftsmanship.
Using a data file generated by a 3D scan of the diamond by non-contact optical measuring devices such as the Sarin (.srn), the VPA software analyzes the angles and direction (azimuth) of facets on the crown and pavilion of the diamond. It calculates each set of measurements and then analyzes how consistent they are around the stone and generates graphical images. The individual facet measurements are averaged and those below the average are colored in cyan and those above are colored in magenta. The greater the degree of deviation from the average the darker the color will be. Thus, at a glance you can see a visual representation of cutting precision which gives insight into the care and craftsmanship of the diamond. (See sample images below).
Samples of Output from the Visual Proportion Analyzer. Click to enlarge.
Precision Standard Faceting – Angles (Basic Report)
Precision Standard Faceting - Facet Direction
Poor Craftsmanship – Angles (Basic Report)
Precision Faceting Non-Standard Facet Directions
"Painting" (Advanced Report)
It is possible to see certain aspects of intentional manipulation of the facets by the cutter to achieve specific goals such as eliminating light leakage or retaining weight. Altering upper and lower girdle facets include techniques known as “painting and digging”. The VPA software makes it easy to assess these sophisticated and subtle aspects of diamond cutting.
The VPA analysis goes well beyond the data contained on a normal lab report. Jewelers and dealers working in the ideal and super ideal cut diamond
realm will be particularly interested. Diamond cutters will also be able to use VPA to assess and adjust their techniques in order to better control their production.
Many consumers may not be interested in the level of detail the VPA software presents, but for those that are interested in well cut diamonds the VPA software provides an immediate, understandable, and intuitive way to observe it.
Diamond cut quality is considered by most experts to be the most important of the diamond “4 C’s”. Ideal cut diamonds exhibit more fire and brilliance than ordinary diamonds and to some extent may also look bigger and whiter because of the quantity of light they return to the eye. They also cost more to produce because of the level of skill required, as well as time and material devoted to hitting all the ideal cut parameters. Astute consumers are willing to pay for premium top craftsmanship and light performance. The VPA is another valuable tool in the arsenal of diamond experts and connoisseurs who want to understand exactly how well their diamond has been crafted.
Providing free diamond software of this nature is a prescient and generous overture on the part of AGSL. Since their inception in 1995 the AGSL has been the world leader in diamond cut quality analysis. The AGS Performance Cut Grade
system is the most technologically advanced, scientifically rigorous, and independently vetted cut grade system available in the world. The AGSL Platinum report is indispensable to consumers seeking the finest in diamond craftsmanship and light performance.