Most collectible are perfectly round pearls and exceptional natural pearls such as melo melo, conch and horse conch pearls with perfect shape and intense colors .
Color: bleaching, deying. Tinting: a treatment which causes a subtle change in colour and/or appearance
Luster: oiling, waxing. Lustre enhancement: Any treatment or process applied to enhance the lustre of a natural or cultured pearl
Luster: working: significantly remove layers of nacreous or non-nacreous material from a pearl, usually to remove blemishes and/or to reshape a pearl, especially blister pearls
Other: filling, irradiation
White, grey, orange, black, brown
Natural pearls form accidentally in the interior of molluscs without interference from man. Most pearls for sale at present are cultured but auctions often still sell jewelry with natural pearls
Special types: Melo melo, Conch, Horse
Cultured: with human intervention which should only stimulate the mollusc to produce a pearl formation and the substance formed should only be that normally produced by the mollusc
Freshwater pearls are mostly cultured and in particular China is a large supplier of them
A perfectly round cultured pearl is worth the highest value. However, a beautiful symmetrical drop shape is also highly valued.
Shape is divided into the following: