Abalone Pearl: Naturally cultivated pearl from an abalone-type univalve mollusk.

Akoya Cultured Pearl: Produced by human intervention (implanting a particle) in varieties of saltwater mollusks. These are usually found in the waters around Japan and China. Colors range from cream, white, rose, gold and blue-gray.

Baroque: Cultured pearl that in asymmetrical, free form in shape.

Biwa Pearl: Cultured pearl cultivated in a freshwater mussel located in Lake Biwa, in Japan. This term is used for any pearl cultivated in a freshwater mussel in Japan.

Blemish: Defect or irregularity found on the surface of the pearl; which can include non-damaging with spots, bumps, pits and wrinkles or damaging with cracks, holes and chips.

Clean: The lack of blemishes on the surface of a pearl.

Conch Pearl: Pearls produced by a conch-type saltwater mollusk in tropical waters. Similar in color to pink coral.

Cultured Pearl: Grown in a mollusk that has been surgically implanted with an irritant particle, through human intervention.

Cultivated Pearl: Same as cultured pearl.

Freshwater Cultured Pearl: Cultured pearl cultivated in a freshwater mollusk from a lake, river or pond, condusive to the proper "farming" of these.

Grafting: The insertion of an irritant-particle into the body or the mantle tissue of a mollusk, by humans in order to produce a cultured pearl.

Imitation Pearl: Man-made or machine-made pearls. Also known as "faux" pearls.

Keshii Pearl: Non-nucleated pearls produced accidentally as a by-product of the cultivating process. Also known as seed pearls and not considered a natural pearl.

Luster: Radiance or sheen of a pearl. The greater the luster the greater the value.

Mabe Pearl: Dome-shaped cultured pearls, grown on the inner shell of a mollusk rather than in its body tissue.

Matching: Pearls of same likeness, shape, luster, size and luster for the purpose of matching with others in creating multi pearl necklace, bracelet or earrings.

Nacre: Calcium carbonate-based crystalline substance produced by a mollusk as a defensive coating against the irritant-particle.  

Seed pearls: Tiny natural baby-pearls weighing under 1/4 grain, usually less than 2 millimeters in diameter.

Semi-cultured: Imitation pearls.

Shape: Description or evaluation of a pearl's shape to determine it's variety, value, or type. The most round in perfection of shape are the more valuable and rare.  

Size: Diameter of a pearl measured in millimeters and used for quality and price evaluation.

Sorting: The separation of pearls by surface, shape, color and size prior to the jewelry matching process.

South Sea Cultured Pearl: Large pearls cultivated in the white-lip oyster. They may be found in shades of white, gold, silver, cream and champagne.

Surface: Quality evaluation determined by the amount of blemishes on a pearl, ranging from clean to heavily blemished.

Tahitian Cultured Pearl: Cultivated in the black-lip oyster which produces pearls in shades of black, silver, gray, green, orange, gold, blue and purple.

Wild pearl: Natural pearls.