How To Grade Pearls By Its Matching?

Matching refers to all previously discussed factors: size, color, shape, luster, nacre and surface quality. Matching applies to pair of pearls and strand of pearls. AAA+ and AAA grade pearls are excellent to very good matching. AA+ and AA grade pearls are very good to good matching. A+ and A grade pearls are good matching.
How to put all the pearl grade factors together: A Pearls grade and value depends on how it combines the complete mix of these seven value factors. Since two strands of pearls in exactly same size maybe very different in other factors such as different color, different surface quality, so pearls are graded based on all other six factors. Additionally, not each of the factor weights the same. According to Gemworld International's Pearl Guide, the following percentages apply to the six factors except size: Color = 10% Shape = 15% Luster 25% Nacre = 25% Surface quality = 20% Matching = 5%. Total 100% n