Glossary of Pearl Terms T
Tahitian cultured pearl: Produced by a black-lip mollusk (Pinctada margaritifera) in French Polynesia.
Tahiti cultured pearl: Produced by a black-lip mollusk (Pinctada margaritifera) in French Polynesia.
Tahiti Black Pearl Promotion Association: Founded in 1994 to promote Tahitian cultured pearls in the United States.
Takara pearl: Imitation pearl made with a mother-of-pearl nucleus.
tank: Indian unit of weight equal to 72 grains or 24 ratis.
Tavernier, Jean Baptiste (1605 to 1688): Frenchman of great influence in the natural pearl trade who developed a system of grading known as ?Tavernier?s Rule.?
Tavernier?s Rule: Seventeenth century valuation procedure that multiplies the size factor, or grain weight of a pearl, by itself, and then by a quality factor ranging from 0.5 to 30 that is based on shape, color, luster and surface to arrive at the value of a natural pearl.
te ufi: Term for black-lip mother of pearl used by original inhabitants of French Polynesia.
teri: Japanese term for luster.
third-generation cultured pearl: Freshwater or saltwater cultured pearl whose growth is started either by implanting a shell bead nucleus in an existing pearl sac from which a second-generation cultured pearl was removed, or by letting the mollusk grow a beadless cultured pearl in an existing pearl sac from which a second-generation cultured pearl was removed.
third graft: Cultured pearl grown in an existing pearl sac after the second harvest. The term is inaccurate because no tissue graft is involved.
three-quarter cultured pearl: Bead-and-tissue-cultured pearl, most often akoya, that is worked to remove an imperfection, leaving a flat portion of the nucleus exposed. The flat side is usually half-drilled and mounted on a post in a setting that conceals the worked side.
tinting: Dilute color dye treatment that produces a slight change in a pearl?s color, usually making it pink.
tissue-cultured pearl: Freshwater cultured pearl whose growth is started by implanting a donor-mollusk mantle-tissue piece in a host mollusk?s mantle.
tissue method: Implanting a freshwater host mussel with a donor-mussel mantle-tissue piece to start the growth of a beadless cultured pearl.