Dyeing can produce just about any color pearls come in. Silver nitrate has long been used to stain pearls a silvery-black. Organic dyes are used most commonly to produce golden pearls. Dyed black and golden pearls should be tested to distinguish them from Tahitian Black and South Sea Golden pearls.

Dyeing is typically applied after drilling, and frequently leaves color concentrations in cracks, fissures, and drill holes. These dye residues can be difficult to see, particularly in strung pearls, so detection requires careful visual examination under magnification.