Pearls are organic in origin. A pearl – is made when a bivalve creature – such as an oyster or clam – builds up a protective layer of nacre around a piece of grit or a foreign body as a defence against that which has found its way into the shell. The nacre builds up in layers and the refraction of light through these layers is what gives lustre to the pearl. The colour is determined by the natural colour of the nacre in the mollusc, but pearls are often dyed many colours.

It is a June birthstone and in the Zodiac circle - the one of Pisces, Cancer and Gemini.

Fine pearls occur without human intervention, but often many molluscs must be opened before a pearl is found, which makes natural pearl very expensive. Cultured pearls are farmed and small beads are introduced to the mollusc to encourage a build-up of the nacre around them.

Pearls are believed to represent faith and are worn to experience peace and tranquillity. They have a gentle energy – helpful for fertility purposes. Pearls also harmonize the emotions and ease mood swings, as well as balance water within the body, easing fluid retention.

Pearls’ keshi – in a sense it is an unsuccessful pearl, as it happens that the grafted nacre rejects the nucleus, retaining in the gonad only the little griffon. Lacking a clearly defined shape, it nonetheless manages to stimulate the production of aragonite. As a result, the nacre produces a natural pearl with a highly irregular form and without a nucleus and can be dyed to different colours.