Most cultured pearls undergo some type of post-harvest processing. These procedures generally include cleaning and buffing the pearls. Off-color pearls might be dyed or irradiated to permanently change their color. These are considered treatments.Common Post-Harvest Processing

Cleaning

Cleaning removes residue the mollusk left on the pearl.

Bleaching

Bleaching removes dark areas. Tahitian and South Sea pearls are seldom bleached.

Buffing

Buffing, with or without a polishing compound, removes surface imperfections.

Treatments

Dyeing, irradiating, and coating are considered treatments.

Dyeing

Dyeing alters the basic pearl color.

Irradiation

Irradiation permanently alters the pearl's color.