Here is a list of pearl terms that might help you better understand this site and the discussions within the community forum. It is compiled from multiple sources and we believe it to be one of the most comprehensive lists available.

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gajamukta: So-called pearl said to come from the heads or tusk sockets of elephants; also called elephant pearl.

gajamuthu: Same as gajamukta and elephant pearl.

ganglia or ganglions, plural, ganglion, singular: Groups of nerve cells that make up the nervous system of a bivalve mollusk.

gastropod: Univalve mollusk, including land and sea snails, with a head and eyes.

gamma ray irradiation: Method of darkening freshwater pearls and the mother-of-pearl core of bead-nucleated saltwater pearls by altering the trace element manganese.

gem quality: Perfectly clean pearl exhibiting fine color and luster.

giant clam: Tridacna gigas, a non-nacreous natural pearl producer that is listed as a threatened species in Appendix II of the international CITES treaty.

giant clam nucleus: Bead nucleus formed from the shell of a giant clam. It is a violation of the international CITES treaty for any signatory nation to import or permit the use of wild giant clams for any purpose.

GIE Perles de Tahiti: (GIE = Groupement d'Interet Economique) Government organization responsible for regulating the Tahiti cultured pearl industry and promoting its products. GIE ceased operations in 2007.

GIE Poe Rava Nui: Cooperative of Tahitian pearl producers and wholesalers.

GIA: Gemological Institute of America, nonprofit school and gemological laboratory founded in 1931; headquarters are in Carlsbad, California.

GIA pearl grading system: Grading system for cultured pearls; developed by GIA in the late 1990s.

glacier pearl: Imitation abalone pearl made from abalone shell.

glass nucleus: Bead used to produce imitation pearls like the Majorica brand.

glochidia: Freshwater mussel larvae.

gold-lip mollusk: Pinctada maxima mollusk used to produce of natural-color gold South Sea pearls. The outer edges of the shell interior are gold in color.

gonad: In saltwater bivalve pearl-producing mollusks, the reproductive organ where a bead nucleus or nuclei and donor-mollusk tissue piece or pieces are implanted to produce cultured pearls.

graduated strand: Strand of pearls with 3 mm or more gradation from the ends to the middle, with the largest pearl as the center.

graft tissue: Donor-mollusk mantle tissue piece implanted with or without a bead nucleus in a host mollusk to produce a cultured pearl.

graft: To insert a piece of graft tissue with or without a bead nucleus in a host mollusk to induce it to produce of a cultured pearl.

grain: Unit of weight associated with natural pearls. One grain equals 0.25 carat.

greffon: Term used in French Polynesia to describe the grafting process.