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Glossary of Pearl Terms A

Glossary of Pearl Terms A

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abalone blister pearl: Nacreous natural half-pearl formed on the inside of an abalone shell.

abalone cultured blister pearl: Nacreous pearl cultured by attaching a half-round nucleus to the inside of the abalone shell. At harvest, the shell is cut around the blister, leaving the nucleus and shell intact.

abalone mabe pearl: Nacreous cultured blister pearl that is separated from the shell at harvest. Its half-round nucleus is removed, the cavity is filled with epoxy resin and backed with a mother-of-pearl disk.

abalone pearl: Nacreous natural whole pearl formed in the body of an abalone.

abas: Unit of weight historically used in Persia to valuate natural pearls. One abas is equivalent to 0.91 carat.

Abernethy Pearl: Discovered by Bill Abernethy in Scotland in 1967. This natural freshwater pearl weighs 44 grains.

abyadh: Historical Persian quality factor for the best color natural pearl (white color).

acid test: Method of testing the authenticity of a natural or cultured pearl with hydrochloric acid. This destructive test is often used by pawnbrokers.

adductor: The muscle that opens and closes a bivalve mollusk?s two shells; it is sometimes cooked, eaten and considered a delicacy.

Ago Bay, Japan: The location of the Mikimoto?s first pearl farm and still the home of many akoya farms today.

akoya: The Japanese name (akoya-gai) of the Pinctada fucata martensi mollusk used in cultured akoya pearl production.

akoya keshi: Small pearl found in the akoya mollusk where it forms as a byproduct of the pearl culturing process.

akoya pearls: Natural or cultured pearl from an akoya mollusk.

alabaster pearl: Imitation pearl made from an alabaster bead that is coated with iridescent lacquer.

ama: The historical female pearl divers of Japan. There were two types: the kachido (those who worked alone) and the funado (those who worked with a partner from a boat, typically the husband).

Amami Gold Pearl: Pearl first produced by the Tasaki Shinju Company in the Pinctada maxima mollusk on the Ryukyu Islands of Japan; known for its better-than-average luster.

American pearls: Natural pearls found and cultured pearls grown in the waters in and around the Americas.

aniline dyes: Synthetic organic (contain carbon) agent used to artificially produce dark colors in cultured pearls.

Antilles pearls: Imitation pearls made from the spindle of trochus or turbo shells.

aragonite: Calcium carbonate crystals stacked in a brick-like pattern; a component of nacre and mother-of-pearl.

atlas pearl: Imitation pearl made from atlas spar.

atoll: A ring of coral that nearly or wholly encircles a lagoon. Atolls are considered the best place to farm cultured pearls in the Pinctada margaritifera mollusk.

Atrina pearls: Dark pearl produced by Atrina vexillum in the Gulf of California.

awabi pearls: Japanese abalone pearl found in the gastropod Auris marina.

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Glossary of Pearl Terms B

Glossary of Pearl Terms B
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baby pearl: Also called ?indicator pearl.? South Sea pearl from Indonesia grown for a short period to produce a pearl sac. The nacre is typically very thin and the quality low.

baroque: A pearl shape; irregular and not symmetrical.

Basra pearl: Named after the town of Basra in Iraq. Name given by Indian dealers to freshly harvested natural pearls from this area.

baten: Historical Persian quality factor describing a button pearl.

baythawee: Historical Persian quality factor describing an oval pearl.

bead-and-tissue-cultured pearl: A freshwater or saltwater cultured pearl whose growth is started by implanting a shell bead nucleus and a donor-mollusk mantle-tissue piece in the mantle, gonad, or other body part of a host mollusk.

bead-cultured pearl: A freshwater or saltwater cultured pearl whose growth is started by implanting a shell bead nucleus in an existing pearl sac from which a first-generation cultured pearl was removed.

bell pearl: Historical term used to describe a natural, pear-shaped pearl.
Big Pink Pearl: Listed in Guinness Book of World Records as largest natural abalone pearl from the Haliotis rufescens, weighing 469.13 carats.

Bironite: Trade name for a non-organic nucleus composed of dolomite.

bivalve: A mollusk from the class Bivalvia having a two-part shell attached by a hinge.

Biwa pearl: Pearl grown in Hyriopsis schlegeli freshwater mussel in Lake Biwa, Japan. Term is often incorrectly used to describe freshwater pearls in general.

Biwako pearl: The name first given to a Biwa pearl.

black-lipped mollusk: Pinctada margaritifera and Pinctada margaritifera cumingi mollusk.

black pearl: A pearl of naturally dark colors produced by the Pinctada margaritifera, Pinctada margaritifera cumingi, Pinctada mazatlanica and Pteria sterna mollusks.

bleaching: A common whitening treatment applied to most cultured akoya and freshwater pearls, and occasionally applied to cultured South Sea and Tahitian pearls.

blinking: An optical phenomenon created by light reflecting from mother-of-pearl remnants on the shell bead within a cultured pearl. Blinking often proves a cultured pearl is bead-nucleated and often indicates a thin nacre coating.

blister pearl: Pearl attached to the shell of the host mollusk. These can occur naturally when a pearl sac bonds with the upper mantle or by human intervention when a hemispherical nucleus is attached to the inner shell by a grafting technician.

blue pearl: Name given to a cultured mabe pearl grown in the Haliotis iris abalone shell.

bodycolor: The aspect of a pearl?s color that is caused by pigment as opposed to light interference.

Bourgignon pearls: Imitation pearls popular in 18th and 19th century France.

brailing: Technique of using a row of hooks to drag the bottoms of southeastern US rivers to collect mussels.

Brewster?s theory: Developed in 1814 by Sir David Brewster, it attributed the iridescent colors of mother-of-pearl to light diffraction from the surface structure.

Broome pearl: Australian cultured South Sea pearl of the 1960s, exhibited a silver hue.

bu: Historical Japanese linear measure still used today to designate the diameter of a bead nucleus. One bu equals 3.03 mm.

Buddha pearl: The first cultured blister pearl produced by the Chinese by implanting a Buddha-shaped nucleus between the mantle and shell of freshwater mussels in the late 1200s.

buffing: A post-harvest method of removing organic residue from pearls and polishing their surface.

buoys: Used to float lines from which mollusks are hung in net panels or other holding devices.

Burmese pearl: Historic term given to a natural Pinctada maxima pearl with a golden or yellow hue.

burnt gold: Also called burnt orange. The most desirable color of gold South Sea pearls; they exhibit a deep gold to dark orange or reddish bodycolor.

button pearl: A dome shape pearl with a flat side. Button shapes are classified as high or low depending on the height of the dome.

byssus: Structure composed of thread-like tissue that bivalve mollusks use to anchor themselves to a solid external surface.

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Glossary of Pearl Terms C

Glossary of Pearl Terms C

Pearls Necklace Price

cabochon: In gemology, a usually round or oval shaped gemstone with a domed top and flat bottom; hence, a pearl of that shape.

calcareous concretion: Whether nacreous or not, all pearls are calcareous concretions.

calcite: A crystalline form of natural calcium carbonate that, together with aragonite and conchiolin, makes up the structure of nacre.

calcium carbonate: Pearls are composed of calcium carbonate (CaCO3) and other elements and substances.

candling: Examining a pearl in front of a focused light source to determine if it shows the layered structure that proves it contains a bead nucleus.

carat: A weight measure sometimes used for natural pearls. It equals 4 grains, 200 milligrams or 0.007054 oz.

Cassis pearl: Yellowish brown pearl produced by gastropods of the genus Cassis.

cave pearls: Stalactite pearls of a brown color, concentric layers and, sometimes, a pearly luster.

Ceylon pearl mollusk: The Pinctada radiata mollusk known for producing natural pearls in the Gulf of Mannar, the Red Sea and the Persian Gulf. According to some taxonomists, Pinctada radiata is a synonym for Pinctada imbricata, Pinctada fucata and others.

chau: Historical unit of weight used in the natural pearl trade in India, also called chov.

chaplets: Line extensions of a pearl farm?s long line system that are secured to the shells.

chemical dyes: A method used to alter the natural color of a cultured pearl.

cherry: A reddish overtone often found on pearls produced by Pinctada margaritifera.

chloride vapor deposition: A superficial pearl coating/coloring agent experimented with in the 1960s.

choker necklace: A strand of pearls that lies above the collar bone, 14 to 16 inches in length (35 to 41 cm).

chov: See chau.

CIBJO: (Conf?d?ration Internationale de la Bijouterie, Joaillerie et Orf?vrerie), also known as the World Jewellery Confederation, is an international confederation of jewelry, gemstone, horology, and silverware trade organizations. CIBJO publishes The Pearl Book: Natural, Cultured & Imitation Pearls?Terminology & Classification.

circled pearl: Pearl with raised concentric rings around its surface, thought to be produced by the developing pearl rotating during growth.

clam pearl: Non-nacreous pearl found in clams.

coating: A layer of artificial or natural substance applied to pearls to enhance luster, surface quality or to produce other optical effects.

coconut pearl: So-called ?pearl? said to be found in coconuts.

coin pearl: Bead-and-tissue-cultured pearl shaped like a coin.

collar: A strand of pearls that measures 10 to 13 inches (25 to 33 cm).

composite cultured blister pearl: See mabe.

composite pearl: Two separate pearls conjoined to give the appearance of a single pearl.

concentric structure: The layering of calcium carbonate crystals that is characteristic of natural pearls, tissue-cultured pearls, bead-cultured pearls and the nacre layer of bead-and-tissue-cultured pearls.

conch pearl: Non-nacreous pearl produced by the conch shell.

conchioline: The organic substance that acts like glue, binding calcite and aragonite crystals together.

condari: Historical Chinese unit of weight used to evaluate pearls; associated with the weight of a grain of wheat or rice.

cool hues: Colors from reddish purple to greenish blue to yellowish green from the GIA color reference chart.

coque de perle: Imitation pearl made from the Nautilus shell (also see Osmenda pearl).

corn flake shape: Second generation pearl that the Chinese mistakenly call ?keshi.? They are shaped like breakfast cereal corn flakes.

Cortez pearls: Trade name forthe pearl cultured inPteria sterna in the Gulf of California, which is also called the Sea of Cortez.

CP&J City: China Pearls and Jewellery City. The world?s largest pearl and jewelry trade center; under construction in Shanxiahu, Zhuji, Zhejiang, China. The first phase opened in April 2008.

Cristaria plicata: The cockscomb mussel first used in Japan and China in cultured freshwater pearl production.

cross shape: Tissue-cultured pearl grown in the shape of a cross.

cultured pearl: Pearl produced by the human insertion of a bead, a tissue graft, or a bead and tissue graft in a freshwater mussel or saltwater mollusk.

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Glossary of Pearl Terms D

Glossary of Pearl Terms D

Pearls Necklace Price
dadjin: A 19th-century pearler?s basket used to hold mollusk shells and a knife.

dana: Historical Persian quality factor describing a perfect round natural pearl larger than 7 mm.

diffraction: One of the ways nacre layers interfere with light, possibly causing light to split into its component colors (the spectrum), one or more of which can be displayed as overtone and/or orient.

Dobo pearl: An Indonesian Pinctada maxima pearl grown on the Aru Island of Wokam prior to World War II. It is said that 9 mm cultured akoya pearls were used as nuclei.

dolomite nucleus: See Bironite.

Dom?: Trade name for cultured American blister pearl produced with a nucleus that remains in the blister when the shell is cut around the pearl?s perimeter.

drop: A symmetrical pearl shape that?s round on one end and tapers almost to a point on the other. The shape can be short or long and takes its name from a water drop or teardrop.

dust pearl: Historical term describing a natural pearl smaller than 2 mm. See seed pearl.

dyeing: Artificially coloring pearls using a dye.

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Glossary of Pearl Terms E

Glossary of Pearl Terms E
Pearls Necklace Price

Edison Pearls: Large beaded freshwater pearls grown in the mollusc gonad in lieu of the mantle. See also Ming Pearls.

EDXRF: Energy dispersive X-ray fluorescence is a spectrometric method of determining chemical composition. It is used to differentiate cultured and natural pearls.

egg shape: Oval shape pearls.

EGL: European Gemological Laboratory.

Ehime Pearl Guild system: Point system developed in 1993 to give farmers exact information about how certain criteria are used to evaluate akoya pearls in Japan.

eightway roller: Perfectly round pearl.

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

endoscope method: Method of testing whether a pearl is natural or cultured; conducted by inserting a hollow needle into the drill hole of a pearl and examining the behavior of a ray of light projected through the hole and reflected from a small mirror at the end of the needle. The light reflects and bends with the concentric layers of a natural pearl and shines out the drill hole. The light enters the roughly parallel layers of a cultured pearl?s bead and travels through them to the surface.

epithelial cells: Cells on the shell side of a mollusk?s mantle tissue that produce mother of pearl and nacre.

epithelial graft tissue: Piece of mantle tissue from a donor mollusk implanted with a mother-of-pearl bead in the gonad or other body part of a host mollusk to produce a cultured pearl; or implanted with or without a bead in the mantle of a host mollusk to produce a cultured pearl.

essence d?orient: Paste made of several ingredients including scales from the undersides of certain fish. It is applied as a coating to glass beads to make imitation pearls; also called pearly essence.

exotic freshwater pearls: Cultured freshwater pearls that exhibit uncommon colors like green, gold, blue or orange.

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Glossary of Pearl Terms F

Glossary of Pearl Terms F

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faceted cultured pearl: Pearl carved to create rhombic or triangular surface shapes that produce a sparkling optical effect when the wearer moves.

fancy colors: Most often associated with cultured freshwater pearls, consist of unusual colors like intense pink, orange or plum.

fancy shapes: Most often associated with cultured freshwater pearls, consist of unusual shapes like bars, crosses, letters, dragons and triangles.

faux pearl: Any imitation pearl.

feather pearl: Cultured pearl gown in the (fancy) shape of a bird feather.

feeding pearl: Legend in India that describes feeding a pearl to a rooster to let its digestive acids restore the original beauty of an old pearl.

first-generation cultured pearl: Freshwater or saltwater cultured pearl whose growth is started by implanting a tissue piece, or a bead nucleus and tissue piece, in a host mollusk that has not grown a pearl before.

fitaam: Wooden nose clamp used by natural pearl divers in the 19th century.

fjeris: Folk songs developed and sung by the pearl divers while on pearling ships in the 19th century.

flame structure: Optical effect commonly associated with conch pearls; produced by aragonite crystals arranged in two directions that are often intertwined.

floor system: Method of pearl farming used in Australia where mollusks are placed in baskets attached to posts or fences and left on the seabed.

flower pearl: Cultured freshwater pearl grown in the (fancy) shape of a flower.

folded crown mussel: Common name for Cristaria plicata, a freshwater mussel that?s also called the cockscomb mussel.

fossil pearl: Pearl that has fossilized and usually dates back to the Pliocene and Miocene periods.

free suspension: Method of pearl farming where mollusks are suspended in wire or nylon panels.

French dye method: Method of dyeing natural and cultured pearls using an organic coloring agent; originated in France.

French river pearl: Imitation pearl made from the hinge of Pinctada shells.

Freshadama pearls: Trade name for freshwater pearl strands composed of loose, gem-grade freshwater pearls exhibiting orient.

freshwater pearl: Pearl grown in a mussel in a non-saline environment.

fuhyu pearl: Chinese name for natural or cultured abalone pearl found or grown in Haliotis discus.

Fujita, Masao: Known as the father of the cultured freshwater pearl industry, Fujita was the first to culture whole freshwater pearls in Lake Biwa, Japan.

Fujita rose pearl: Freshwater pearl from Lake Biwa first developed and marketed by Dr. Masao Fujita in 1930. The pearls were produced by implanting a drilled mother-of-pearl bead and a donor-mussel tissue piece in the host mussel?s soft body.

funado: Kind of ama (Japanese pearl diver) who worked with a partner and a boat.

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Glossary of Pearl Terms G

Glossary of Pearl Terms G

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 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.

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Glossary of Pearl Terms H

Glossary of Pearl Terms H

H-grade pearl: Letter grade assigned to a high-grade pearl by Japan?s Pearl Inspection Office from 1952 to 1999.

half-drilled pearl: Pearl drilled to 2/3 or 3/4 of its diameter for setting in pearl jewelry.

half-light pearl: One of four Saxony quality factors used to describe natural German river pearls. See also: light pearl (highest quality), and sand and rotten pearl (lowest qualities).

half-round nucleus: Nucleus used to produce cultured blister pearls. A half-round nucleus has a domed side and a flat side; the latter is attached to the host?s shell.

Haliotis: Large genus of gastropods commonly known as abalone.

hamadera auction: First cultured akoya pearl auction, January 8, 1920, Osaka, Japan. Two kilograms of Mikimoto?s pearls were sold at the auction.

hama-age: Newly harvested cultured akoya pearls in Japan.

hama-age auctions: Annual auctions of newly harvested cultured akoya pearls in Japan.

hammer pearl: Brownish-black natural pearl produced by the hammer shell, Malleus malleus.

hanadama: Highest quality portion of a cultured akoya pearl harvest.

hanadama certification: Cultured akoya pearl certificate issued by the Pearl Science Laboratory of Japan indicating cultured akoya pearls that have the highest ratings in all quality attributes.

hankei: Japanese name for a cultured blister pearl.

hardness: Pearls range from 3.5 to 4.5 on the Mohs hardness scale.

harvest: Removing cultured pearls from mollusks on a pearl farm.

heat treatment: Applying heat to a natural or cultured pearl to improve its luster.

Heath pearls: Natural pearls from the Heath region of Scandinavia; popular in the latter half of the 19th century.

Hepu pearls: Natural pearls collected from Hepu and Behai in Guangxi Province, China, as early as the Han dynasty (206-220 AD).

hinge pearl: Natural pearl found near the hinge of a bivalve mollusk, typically of elongated, irregular shape.

hollow pearl: Natural or cultured pearl with a large, hollow cavity.

Hope Pearl: Natural marine blister pearl weighing 1,816 grains (454 carats), probably from Pinctada margaritifera.

hue: First impression of a pearl?s color.

hybrid mussel: Pearl mussel created by crossbreeding two species.

hypostracum: Mother-of-pearl layer of a pearl-bearing bivalve mollusk shell, the shell layer adjacent to the mantle.

Hyriopsis genus: Unionidae family mussels native to Southeast and East Asia. Pearl-producing species of the genus occur in China and Japan.

Hyriopsis cumingi: Triangle shell mussel native to China, used extensively in cultured freshwater pearl production.

Hyriopsis schlegeli: Biwa pearly mussel native to Japan, used to produce tissue-cultured freshwater pearls in Lake Biwa. Also used in China since the mid-1990s as a pure species and as a hybrid with Hyriopsis cumingi.

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Glossary of Pearl Terms I

Glossary of Pearl Terms I

I-pearls: Imitation pearls from Izumi, Japan.

icon pearl: Cultured blister pearl produced in the shape of an iconic object by using a nucleus of that shape.

IGI grading system: Cultured pearl grading system developed by the International Gemological Institute in New York in 1993. The system uses 22 reference strands to grade color, luster, nacre, shape and surface according to point values ranging from 1 (lowest) to 30 (highest).

ikecho-gai: Japanese name for the Biwa pearly mussel, Hyriosis schlegeli. Translated to English, ikecho-gai is pond butterfly shell.

image pearl: An image pearl, similar to an icon pearl, is a cultured blister pearl in the shape of an image like a Buddha or a dragon; first cultured in Cristaria plicata (cockscomb) mussels in China in the late 1200s.

imitation pearl: Any material that simulates the appearance of a cultured or natural pearl but does not possess either?s physical properties.

immature pearl: Natural pearl that shows discoloration from a conchiolin core or darkened conchiolin rings.

imperial golds: South Sea pearls from the gold-lip pearl mollusk (Pinctada maxima) that exhibit deep gold color saturation.

Incomparable, The: See Peregrina, La.

indicator pearl: Small South Sea pearl (also known as a baby pearl) harvested from Pinctada maxima after six to eight months so a larger nucleus can be inserted in the existing pearl sac. The pearls are generally small and have thin nacre. Indonesia is the primary producer.

infrared spectroscopy: Method of determining the agents used to change the color of a cultured or natural pearl. It is also used to determine the chemical composition of imitation pearls.

interference: Interference of light by nacre creates the iridescent play of color on the surface of a pearl. Refraction, diffraction and/or thin-film interference occur as light penetrates extremely thin nacre layers.

iridescence: Play of color over the surface of a pearl as interference divides white light into its component colors.

irradiation: Exposing a cultured pearl to gamma rays darkens the nacre of a freshwater pearl or the freshwater mussel bead within a cultured saltwater pearl by affecting the manganese each contains.

Ise pearl: Natural white pearl from Ago Bay, Japan. Cultured akoya pearls eclipsed Ise pearls.

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Glossary of Pearl Terms J

Glossary of Pearl Terms J

Japan Black Pearl Promotion Association: Founded in October 1993, the association promotes cultured pearls from French Polynesia in Japan.

Japanese lingah: Popular name for the Pinctada fucata martensi mollusk.

Japanese pearl mollusk: Akoya pearl mollusk.

Jewelmer: Philippine producer and wholesaler of South Sea pearls, primarily those produced by the gold-lip Pinctada maxima pearl mollusk.

jin: Historical weight unit used to valuate natural pearls in China during the Ming dynasty (1368-1644 AD). One jin equals 500 grams.

jiwan: Historical Persian quality factor describing round, pink natural pearls with high luster.

John Guise School of Pearl Culture: Founded in New Guinea by Australian C. Denis George. The school trained villagers in pearl culture.

Jomon Pearl: The world?s oldest known pearl, believed to be more than 5,500 years old.

JPEA (Japan Pearl Exporters? Association): Founded in 1954, disbanded in 1999 and recently reestablished (with little support), the JPEA is an association of pearl farmers and dealers that works to promote cultured pearls and to ensure that low-grade pearls are not exported from Japan.

JVC (Jewelers Vigilance Committee): US-based nonprofit group that works to ensure legal compliance and ethical standards within the jewelry industry.