Freshwater Pearl

Freshwater pearls are organic gems formed inside freshwater mussels living in rivers, lakes and ponds. A pearl forms when the mussel coats an irritant with layer upon layer of nacre, a combination of microscopic crystals of aragonite (calcium carbonate) and conchiolin, an organic binding protein. The overlapping layers of nacre reflect and refract light, giving pearls their soft glow, known as lustre, and sometimes a rainbow sheen called orient.

Natural freshwater pearls are now extremely rare, and almost all freshwater pearls sold today are cultured. A small piece of mantle tissue from another mussel is inserted into the host mussel, which then builds a pearl around it. Because most freshwater pearls have no bead nucleus, they are almost solid nacre, making them durable and resistant to peeling. A single mussel can produce many pearls at once. China is by far the largest producer, with Japan's Lake Biwa, once famous for freshwater pearls, now producing very few.

Freshwater pearls come in many shapes, including round, near-round, button, oval, rice, potato, coin, stick and irregular "baroque" shapes, as well as keshi pearls. Their natural colours include white, cream, pink, peach and lavender; other colours such as black, blue, green, gold and bright pinks are usually dyed or treated. Round, highly lustrous freshwater pearls can now rival saltwater pearls in appearance.

Imitation pearls include glass and plastic beads coated with pearl essence, and "shell pearls" made from mother-of-pearl coated with a pearly finish. A traditional test is to rub a pearl gently against the edge of a tooth: real pearls feel slightly gritty, while imitations usually feel smooth.

Freshwater Pearl at a glance

Caring for freshwater pearl

Pearls are soft (2.5 – 4.5 on the Mohs scale) and sensitive to acids, chemicals, heat and dryness. Put pearls on last, after perfume, hairspray and cosmetics, and wipe them with a soft, slightly damp cloth after wearing. Never use ultrasonic or steam cleaners or detergents. Store them flat in a soft pouch, separate from other jewellery, and avoid sealed plastic bags, as pearls need a little moisture. Pearl necklaces should be restrung periodically, ideally knotted between each pearl.

In folklore

The beliefs below are traditional folklore, included for interest. They are not scientifically proven, and nothing here is medical advice.

Pearls have been treasured for thousands of years and appear in the myths of many cultures. Ancient Chinese legend held that pearls came from the brains of dragons, while Persian myth described them as tears of the gods, and Greek legend linked them with Aphrodite, goddess of love. Pearls were once considered the most valuable of all gems. Cleopatra is said to have dissolved a pearl in vinegar and drunk it to win a wager. Pearl is the birthstone for June and the traditional gift for a 3rd and 30th wedding anniversary, and is associated with the zodiac sign Cancer and Gemini.

Pearls are traditionally regarded as symbols of purity, wisdom and integrity. Crystal healing lore holds that they bring calm and emotional balance, soothe the mind and encourage sincerity and loyalty. As gems of the water, they are associated with the moon and with feminine energy, and are linked to the heart and crown chakras.

Related stones

Akoya pearls, South Sea pearls, Tahitian pearls, keshi pearls, mabe pearls, natural pearls and conch pearls. Other organic gems include mother of pearl, shell, coral and amber. Imitations include shell pearls, glass pearls and plastic pearls.

For the technically minded

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