Crown Angles Round Brilliant Cut

The crown angle is the angle between the bezel facets and the girdle plane. It primarily affects dispersion or the fire in a diamond.

The AGS Ideal 0 Cut grade includes a narrow range of crown angles from 33.7 degrees to 35.8 degrees.

Diamonds with ideal to very fine cut proportions have crown angles between the ranges of 32.2 and 36.8 degrees. It is difficult to visually recognize differences in the appearance of diamonds that have crown angles within the range of ideal to very fine.

Shallower crown angles produce less fire, especially if the diamond has a large table. When the crown angle is below about 32 degrees, it can reduce durability by making the diamond susceptible to chipping. In contrast crown angles steeper that 36 degrees give the diamond a lumpy, top-heavy appearance, and disrupt the balance of fire and brilliance.  High crown angles also cause darkness under the bezel facets.

If you have any more questions concerning crown angles or proper cut proportion, contact our Certified Gemologist-Appraisers toll free at 1-800-766-7119.