Probably the single most important thing to understand when learning about Pearl Grading in order to make an educated purchase decision is this: it is impossible to compare grades and grading systems from one company to another.
Unlike diamond grading, there is no standardized grading system for pearls. Every company in the world that grades and sells pearls is using a system that they themselves devised and created. Every system is subjective and every system is unique. We know with certainty, for example, that our AA+ graded akoya pearls have better luster, surface and color than another online sellers' AAAA pearls exhibit. This is the unfortunate result of no standardized, universal grading system.
The following is the grading system we adhere to for akoya pearls.