How Are Pearls Formed

A natural pearl might start with an itch, although most pearl experts now agree that the 'grain of sand' is nor more than a myth.

When a small seed of material such as a parasite becomes trapped within an oyster or mussel's shell, nature gets to work. The shellfish slowly deposits layers of organic material called nacre around the source of its irritation.

Nacre is made from two forms of calcium carbonate called Aragonite and Calcite, which are found in the interior lining of shellfish that is often called ‘mother-of-pearl’. These are linked together by a little organic protein called Conchiolin, which is identical to that found in human hair and fingernails. Together these substances form the nacre.

Over time, layering of this nacre by the shellfish forms a smooth surface around the foreign material slowly transforming it into a beautiful pearl, unique in its shape, size and colour. The difference from one pearl to another lies in the shape and placement of crystals of Aragonite and Calcite that are being held in place by Conchiolin.

In our next articles we shall look at the differences between natural and cultured pearls.