One more thought on crown & pavilion angles for the perfectionist
Is it possible for any single round or fancy shaped diamond to have more than one crown angle or pavilion angle? You bet! In fact a round diamond can be checked anywhere on its circumference and fancy shaped diamonds, usually checked at the 3 and 9 clock positions, can also be measured slightly off those positions to render multiple crowns and pavilion angles.
Now here is the million dollar question. When a lab grading report appraisal is done, which crown and pavilion angle are you given? Are you given the best one? Probably. The worst one? Not likely. In an ever competitive race for your dollar, the cutter, the jeweler, and even the appraiser can be caught up in “warping.”
Warping is the placement of accurate pavilion and crown angles on the diamond but solely in one location. The rest of the crown and pavilion angles are off to the benefit of weight retention. There are two types of warped diamonds – inward and outward. An inward warped diamond may have the side of the pavilion slightly curved to pickup the correct measurement. In an outward warped diamond there is a slight bulge in one location above or below the girdle. Warps to a good cutter can make that cutter many more dollars. Knowing that most labs and appraisal services check for the best measurement or an average lets a cutter push through a diamond as a class 1 or 2 when in actuality it is a class 3 or 4 (a poorly proportioned diamond).
In purchasing your diamond don’t be afraid to ask the question, “Is the crown and pavilion on my diamond based on a single measurement, an average or on the worst?”
If a diamond’s worst crown and pavilion angles are acceptable then surely the rest will be as well. You can also ask for minimum and maximum pavilion and crown angles to see the extremes in both directions. If a jeweler doesn’t know how the angles are derived then I would not put much faith in the numbers he tells you.
PS: The only two pieces of equipment that can accurately check for warping are Sarin and Megascope machines. Also see Diamond: Parts of the Stone.
by Fred Cuellar, author of the best-selling book “How to Buy a Diamond.” More questions? Ask the Diamond Guy®