As with any gem material, the size, location and nature of imperfections will greatly influence the value of the item. Cultured pearls showing pits. Matching is used to match pairs or match for necklaces. Pearls are uniform and are as close as possible to each other. Mikimoto's cultured pearl was timely in the sense that the world supply of natural pearls had been going down due to overfishing, pollution and other more attractive occupations than the work of pearl diving.
Blemishes can include spots, bumps, pits, holes, cracks, chips, wrinkles and dull spots.
Blemishes fall into two categories, damaging blemishes and non-damaging blemishes.