Real Pearls | Pearls and their shells

To understand pearls you need to know where they come from. All pearls are grown by shelled creatures called molluscs that live in saltwater seas and oceans or freshwater lakes and rivers all over the world. Some oysters and mussels (which are both types of mollusc) have naturally shiny shells, which is amazing in itself. The hard shells of these animals are designed to protect them from being eaten by other creatures, not to look pretty. Molluscs live at the bottom of seas and lakes where it’s dark and so they have no benefit from being shiny, it’s just one of those wonderful coincidences

But why are we waxing lyrical over shiny shells? The reason is that when foreign things, like small bits of seaweed or tiny crabs, sneak into a mollusc the mollusc will defend itself by covering the intruding object with the same material with which they make their shells. When something gets stuck in us we get a spot or a temperature. Molluscs on the other hand protect themselves by wrapping the intruder with their shell which, some of the time, can be beautifully shiny resulting in a pearl. Isn’t that just incredible?

There are about 85,000 known types of mollusc (which includes snails, slugs and squids amongst others) but only 20 of these have the shiny shells needed to make pearls. It is these 20 remarkable, shiny shelled creatures which make pearls. Their shiny shells are made out of an iridescent material called nacre (pronounced nay-ker), which we now know is the same material that forms pearls. Molluscs which don’t have shiny shells, like the mussels we eat in moules marinières for example, can also cover intruders with their shell, but as it isn’t shiny, the resulting ‘pearls’ aren‘t very attractive, (and they can break your teeth if you’re not careful...).

In this picture of some pearls with their molluscs, it’s easy to see that pearls are made from the same material as the shell...

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