Glossary of Pearls farming
Pearl farming uses a number of technical terms that are useful to know before delving into this universe.
Here are the key words of the pearl farming language:
- Aragonite: Calcium carbonate (CaCO3) that forms part of the mollusc shell and is the essential substance composing pearls.
| Collector: Artificial device (tree trunks, bundles of miki miki, nets, mesh, etc.) used to capture free-swimming oyster larvae, also called spat. |
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- Conchiolin: Organic substance found in small amounts in pearls (about 5%), forming the framework for aragonite crystals.
- Detrocage: The process of separating young oysters that cluster chaotically on collectors. Once separated, each oyster is cleaned, pierced and suspended at an underwater station until it reaches grafting size.
| - Grafting house: A small building, often built on stilts, where skilled grafters operate on oysters. |
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| - Farm: Land and lagoon installations dedicated to pearl cultivation. We speak of pearl farms and pearl farmers. |
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- Natural pearl: A pearl formed spontaneously, without human intervention.
| - Graft: The surgical operation where a nucleus and a graft are inserted into the gonad of an oyster to stimulate pearl formation. A grafter can operate on 300 to 600 oysters per day. |
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| - Graft tissue: A small fragment of mantle tissue from a donor oyster, inserted with the nucleus into the gonad. It develops into the pearl sac. |
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| - Keshi: A type of pearl formed when the oyster rejects the nucleus but continues to secrete nacre around the graft tissue. Keshi pearls are irregular, 100% nacre and without a nucleus. |
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- Luster: The surface brilliance of a pearl when exposed to light; distinct from orient, which is the inner iridescence.
| - Mabe: A half-pearl grown by placing a dome-shaped nucleus against the inside of the oyster's shell, under the mantle. |
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- Mantle: The organ in molluscs that secretes shell material. A small piece of mantle is used for grafting.
- Spat (Seed oysters): The larval stage of bivalves (oysters, pearl oysters, mussels) before settlement. By extension, spat also refers to young oysters fixed on collectors.
| - Nucleus: A bead made from the shell of a freshwater mollusc, usually from the Mississippi River. It is surgically implanted into the oyster along with the graft tissue. |
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- Orient: The iridescent play of light seen in pearls, caused by light interference within overlapping layers of nacre.
- Pearl: A hard, lustrous concretion formed of nacre in concentric layers around a nucleus or irritant inside a mollusc.
- Pearl sac: The pouch created by graft tissue inside the gonad, where nacre is secreted around the nucleus to form a pearl.
- Second graft (Re-grafting): A procedure where a harvested oyster is re-implanted with a larger nucleus in the existing pearl sac to produce a bigger pearl.
| - Station: Submerged installations in the lagoon, between surface and seabed, where oysters are grown before and after grafting. |
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