Pure Pearls Glossary
Bead Nucleated
Grown around a round shell bead, so the pearl is a nacre shell over a core. The saltwater method, and how roundness is achieved.
A polished bead, usually cut from American mussel shell, is implanted with a piece of donor tissue. The oyster coats the bead, and the bead's roundness dictates the pearl's.
Everything then depends on how long the pearl stays in the water. Akoya nacre is often only 0.3mm to 0.5mm thick; South Sea pearls, farmed for years, build 2mm or more.
Thin nacre is the single most common quality failure in saltwater pearls. It shows as a glassy, slightly blue cast, and over years it can blister or reveal the bead beneath.
When you are buying
When buying any saltwater pearl, ask about nacre thickness before you ask about size. A large pearl with thin nacre is a worse purchase than a smaller one with thick nacre.
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Tissue Nucleated
Grown around a scrap of mantle tissue instead of a bead, so the pearl is solid nacre throughout. The freshwater method.
Nacre
The material a pearl is made of: microscopic aragonite platelets glued in layers by conchiolin. Thickness determines both lustre and lifespan.
Akoya Pearl
The classic small round white saltwater pearl from Japan and China, usually 5mm to 9mm. The pearl in a traditional single-strand necklace.
South Sea Pearl
The largest commercially grown pearl, from the gold-lipped or silver-lipped oyster. Typically 9mm to 16mm, white to deep gold.
Not sure what you are being sold?
Paste any pearl description — another shop’s listing, a message from a jeweller, an old certificate — and we will break it down term by term.