Is there a standardized grading system for pearls?

Pearl grading is very similar to the "4 C's" of diamond grading in that the pearl grading system takes into consideration several key categories of qualitative comparison analysis. The pearl grading system consists of five main categories: luster, shape, color, surface, size. Although size will certainly play an important roll in evaluating the monetary value of a pearl, luster, shape, color, and surface quality are of primary importance. There is no standard system in use. We use our own system for evaluating our pearl jewelry, from the lowest to the highest quality: A, AA, and AAA. This system grades pearls on a scale from AAA to A, with AAA being the highest grade, this grading scale is common to freshwater pearl dealers. The AAA to A grades are as follows: AAA: Virtually flawless pearl. Surface luster is very high, and 95% of surface will be free from any defect. AA: The surface will have a very high luster, and at least 75% of the surface will be free from any type of defect. A: The lowest jewelry-grade pearl, with low surface luster and/or more than 25% of the surface showing defects.