Pearls are valued as gemstones although they are not actually minerals, but organic gems. They are the result of a minute particle of foreign matter, such as a fine grain of sand, entering the shell of a mollusc and being coated with the same material that covers the inside of the shell (called nacre, or mother-of-pearl). Eventually, the grain of sand is transformed into a pearl. There is a wide colour range including white, black, grey, pinkish-white, and yellow-white. The name dates back to the 14th century. Many explanations for the origins of pearls were advanced in earlier times, some of them very poetic. According to the old Eastern legend, quoted by the ancient scholar Pliny, oysters rose to the surface of the sea beneath the moon’s rays, opened their shells and were fertilized by drops of dew. It was not until the 15th century that a Dutch scholar recognized the true origin of pearls. Today most pearls are “cultured” – the same kind of oyster is used in a controlled environment to produce the pearls. A round bead or a chip of the Mother-of-Pearl shell is introduced into the oyster which reacts by coating nacre over the foreign body to form a pearl. Because the pearl is formed as the direct result of irritation, it is thought to hold the key to how we can overcome oppression and pain, an example of how to turn insignificant into the sublime and beautiful. the pearl is thought to signify faith, charity and innocence and to enhance personal integrity. It has been used in the treatment of digestive disorders and is thought to increase fertility and ease childbirth. The pearl is one of the birthstones for June (with moonstone and alexandrite), symbolizing health and longevity.