Cultured versus Natural Pearl

Natural versus Cultured

Natural pearls

Natural pearls are nearly 100% nacre. It is thought that natural pearls form under a set of accidental conditions when a microscopic intruder or parasite enters a bivalve mollusk, and settles inside the shell. The mollusk, being irritated by the intruder, secretes the calcium carbonate substance called nacre to cover the irritant. This secretion process is repeated many times, thus producing a pearl. Natural pearls come in many shapes, with round ones being comparatively rare.

Cultured pearls

Cultured pearls (nucleated and non-nucleated or tissue nucleated cultured pearls) can be distinguished from natural pearls by X-ray examination. Nucleated cultured pearls are often 'pre-formed' as they tend to follow the shape of the implanted shell bead nucleus. Once the pre-formed beads are inserted into the oyster, it secretes a few layers of nacre around the outside surface of the implant before it is removed after six months or more. When a nucleated cultured pearl is X-rayed it will reveal a different structure than that of a natural pearl. It exhibits a solid center with no concentric growth rings, compared to a solid center with growth rings.