I designed the Ideal-Scope as a portable and affordable method to grade the cut quality of diamonds. I have been using it as one part of my secret diamond buying technique for more than two decades. In 2001 we decided to mass produce and make them freely available. The instrument is simply a lens with a hot pink reflector in front of the diamond and a central viewing hole. With it you can see just how much of the red / pink light refracts back from the diamond.
Anyone can intuitively gauge a diamonds brilliance; white areas in a diamond show light transmitted from behind the diamond which we call leakage - the enemy! The blackness of the lens mimics the light obscuration of an observer's head and body; too much is bad and too little indicates the diamond will have poor scintillation. The lens creates the star pattern which indicates the symmetrical quality of the diamond. Symmetrical round diamonds are sometimes sold as Hearts and Arrows (H&A) but a H&A's viewer does not show the leakage which is often present in many H&A's diamonds.
The most brilliant diamonds look bright pink/red with a black star and minimal white or pale areas except for the small 'V' shaped white leakage areas near the edge of the stone.
Typically when buying diamonds I use this process:
Firstly I look at each diamond in a parcel with an Ideal-Scope; I can check about 4 or 5 stones a minute. This usually results in a rejection of 60% to 90% of all supposedly well cut diamonds. Then each stone is examined for Colour (we reject everything below an H master stone) and Clarity (rejecting eye visible and diamonds with reduced transparency). On a buying trip I will examine more than 1,000 diamonds a day.
The idea behind the Ideal-scope was used to develop the ASET scope which I made under license for the American Gem Society. AGS use the ASET as the basis for their Princess and other ‘fancy shaped' diamond cut grading system. OctoNus developed a software visualization program with Moscow State University incorporated Ideal-scope and ASET views into their DiamCalc software. The diamond cutters we work with use this software in the planning of the cutting of larger Holloway diamonds.
Using an Ideal-Scope and an ASET scope
Holloway Ideal Cut
minimal white areas and
a good symmetrical star
lots of white leakage
and random symmetry