Here's a glossary of some common pearl terms, including types and shapes of pearls and necklace lengths. There are some photos to provide examples of some of the definitions. All of the pictures are links - if you click on them you will go to the jewelry description at the Merchant's website. Please let me know if there are any terms you would like to see added and I'll include them.
Abalone Pearl - Pearl produced by the abalone mollusc. Abalone pearls are usually gray with strong orient.
Akoya Cultured Pearl - A type of saltwater cultured pearl, grown primarily in cooler water off the coasts of Japan and China. Oyster species that produce Akoya pearls include Pinctada fucata and Pinctada martensi.
Baroque - Any irregularly-shaped pearl. Baroque pearls are valued for their one-of-a-kind, unusual shapes.
Biwa Pearl - Cultured freshwater pearls grown in a mussel that lives in Lake Biwa, Japan.
Blemish - Refers to any surface defect on a pearl. Blemishes include cracks, chips, dull spots, wrinkles, spots, holes, bumps, and pits.
Blister Pearl - A pearl that has grown onto the inside surface of a mollusc's shell, so that it is dome-shaped on one side and flattened on the other. See also Mabe pearl.
Cultivated Pearl - Another term for a cultured pearl. Any pearl that is intentionally grown by introducing an irritant or substrate inside the shell of a mollusc.
Freshwater Pearl - Any pearl produced by a mollusc living in fresh water.
Grafting - Also termed nucleation or implantation. Process of inserting a hard bead nucleus or piece of soft mantle tissue into a mollusc body or mantle of the mollusc.The nucleus or mantle tissue serves as the 'seed' to irritate the mollusc to produce a pearl.
Imitation Pearl - Any pearl not made by molluscs. Imitation (also called faux, fake, simulated) pearls commonly are made of glass, plastic, or urea, and may be coated with any of a number of polymers, waxes, or fish scale extracts.
Keshii Pearl - Sometimes called a seed pearl or a keshi pearl. This is a small pearl that grows in addition to the intended cultured pearl. It is a non-nucleated pearl.
Luster - A pearl's ability to refract and reflect light. Luster refers to a pearl's depth and shine.
Mabe Pearl - A pearl that grows against the inside wall of a mollusc's shell, resulting in a domed shape with a flattened back. In some cases, mabe pearls are grown by glueing a plastic dome (nucleus) onto the inside surface of a mollusk's shell. Once the nucleus is coated with nacre, the pearl is cut away from the inner shell. The nucleus is removed and the cavity is filled with an epoxy resin and backed by a mother-of-pearl plate. Mabe pearls are sometimes called blister pearls.
Momme - Standard unit of measurement of pearls in Japan. One momme equals 3.75 grams or 18.75 carats.
Nacre - The calcium carbonate-based substance secreted by a pearl in response to an irritant, such as a piece of shell (cultured pearl) or parasite (most natural pearls).
Natural Pearl - Any pearl grown without human interference. Sometimes called 'Oriental' pearls.
Nucleation - Also termed grafting or implantation. Process of inserting a hard bead nucleus or piece of soft mantle tissue into a mollusc body or mantle of the mollusc.The nucleus or mantle tissue serves as the 'seed' to irritate the mollusc to produce a pearl.
Nucleus - Usually, a small rounded piece of shell from an American freshwater mussel. For freshwater pearl cultivation, the nucleus usually is a shaped piece of mantle from another freshwater mussel.
Opera - Pearl necklace that is 28-32 inches in length.
Oriental Pearl - A term sometimes used to refer to a natural pearl.
Peacock Pearl - A type of black pearl, usually with dark green tones. Genuine black pearls are produced by the oyster Pinctada margaritifera. The term 'peacock pearl' often is frequently applied to irridescent black freshwater pearls, which achieve their color as a result of irradiation, heating, and/or dyeing.
Potato - Refers to a pearl with an oblong shape, such that it resembles a potato. Most potato pearls are freshwater cultured pearls from China.
Princess - Pearl necklace that is from 17-19 inches in length.
Rice Pearl - A freshwater cultured pearl with a crinkled surface and elongated shape, such that it resembles a grain of rice. Most rice pearls originate from China or the United States.
Rope - Pearl necklace that is longer than 45 inches.
Saltwater Pearl - Any pearl, natural or cultivated, that is grown in a mollusc that lives in salt (ocean) water.
Shape - A pearl's shape has a great impact on its value. Perfectly round pearls are rare, and therefore highly valuable. Other shapes of pearls include off-round, drop, oval, button, circle, baroque. Freshwater cultured pearl shapes also include stick, angel-wing, cross, and coin shapes.
Size - Pearl size is expressed in millimeters and is a measure of diameter.
South Sea Pearl - Pearls grown in the white-lipped oyster, Pinctada maxima, in the South Pacific. South Sea pearls occur in shades of white, silver, and gold.
Tahitian Pearl - Pearls grown in the black-lipped oyster, Pinctada margaritifera, in the South Pacific. Tahitian pearl colors include deep gray (black), purple, green, gold, and silver.
