Diamond cut is the most important factor in sparkle but the hardest to interpret.

Diamond cut has long been studied and computed and just recently has science gotten a really good hand on it. Now diamond cutters have computer models that they can turn to to determine what the best angles are to cut a diamond to get the maximum sparkle and light return. So you would think that this would be the end of the discussion and that an "Ideal cut" would have been calculated by the computer. It has but by whose computer and does the computer match what people consider to be the best.

Computers vs Humans

Computer programs weighed in and told us what the best cuts were and then gemologist show humans different cuts of diamonds to see if humans would agree with what the computer calculated had the best sparkle. Guess what? The humans didn't always agree with the computer. So they recalibrated the computer and tried again, each time getting better and better.

What does this mean to you?

It means that there are computer programs that can determine very accurately how good a diamond will sparkle based on a few factors.

  • Depth percent
  • Table percent
  • Crown angle
  • Pavilion angle

All these factors can be found on the diamond's certificate or from the seller, if not then don't buy it.

What to do with these numbers?

I could go into a 10 page break down on how all these numbers relate and affect the sparkle but I don't think you want to read that. The best thing to do with those numbers is to plug them into the Holloway Cut Advisor. This program will take those numbers and give you a very accurate breakdown of how well your diamond is cut.

Holloway Cut Advisor (This will open in a new window, if not try holding down CTRL and clicking on the link to override your pop-up blocker.)

Any diamond that scores below a 2 is considered an excellent diamond cut. Better than 95% of all diamonds. Note: this is only for use with round diamonds.