Grading or Valuing pearls

Unlike gemstones such as diamonds, pearls are not judged by a single international standard of quality.  Various systems have been developed for grading pearls on the basis of lustre, colour, size, shape, surface and iridescence. 

There are two contrasting grading systems in use today: the “AAA-A Grading System” and the “A-D Grading System” (the Tahitian grading system).  An example of both systems follows in this section.