Le lexique
Glossaire du commerce des pierres précieuses
Le vocabulaire du commerce des pierres de couleur, tel qu'il est utilisé dans la pratique par les laboratoires et les négociants. Chaque terme renvoie au catalogue qu'il décrit.
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- CabochonA cabochon is a stone polished into a smooth dome without facets, usually over a flat or gently rounded base.
- CaratA carat is the trade's unit of weight: one fifth of a gram, divided into one hundred points.
- Certificate mismatchA certificate mismatch is any disagreement between a stone and the report that travels with it: weight, measurements or inclusions that do not correspond to what sits in the paper.
- Colour zoningColour zoning is uneven distribution of colour within a stone: straight bands, patches or sectors following the crystal's growth.
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- PadparadschaPadparadscha is a sapphire showing a delicate blend of pink and orange, with neither colour winning.
- Pigeon's bloodPigeon's blood is the trade term for the most saturated pure red in ruby: red with no more than a whisper of purple, medium to medium-dark in tone, and lit from within.
- PleochroismPleochroism is the property of showing different colours when a stone is viewed along different crystal directions.
- ProvenanceProvenance is the documented history of a stone after it left the ground: where it has been, who has owned it, which reports and invoices have travelled with it.
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- ToneTone is how light or dark a colour is, independent of how pure it is.
- TrapicheTrapiche is a rare growth pattern in which six sectors radiate from a central core, separated by dark spokes, so the stone looks like a wheel seen from above.
- Treatment disclosureTreatment disclosure is the obligation to state, in writing and at the point of sale, every treatment a stone has received.
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