Grading South Sea and Tahitian Pearls
While there is no internationally recognized number or letter system for pearl grading, there are best-grading practices that are accepted and recognized by all professional pearl dealers within the industry. Understanding grading attributes and quality characteristics of South Sea and Tahitian pearls is imperative to properly shop and compare.
Pearl Grades Are Combinations Of Many Different Value FactorsAs pearls have many differing value factors such as shape, luster, size, and surface quality combining together to produce a unique gem, grading pearls can become very difficult. Although it is possible to grade each value factor individually, most purveyors of this gem rely on a simple letter-grade system. The grading assigned will rarely be absolute, varying from one dealer to the next, but if the seller is honest, the grades should give the consumer a practical basis from which to judge the quality of the sellers wares.
Which System Is Correct? The AAA-A System Or The A-D System?Confusion abounds regarding the use of the A-D system (the Tahitian System) or the AAA-A system, popularized by the late Kokichi Mikimoto. While some pearl dealers swear by one method, another seller may use the other. So which is correct? The answer is simple – they both are.
As there is no International mandated system for grading pearls, nor is there an absolute alphabetical system, both systems are used interchangeably. Their use is largely based on location, but even this is a general rule of thumb, by no means absolute.
(http://www.pearl-guide.com/forum/content.php?r=94-South-Sea-and-Tahitian-Pearl-Grading)
