Most pearls emerge from their watery home without any need for cutting, faceting, or polishing to reveal their shimmering iridescence, lustre and soft inner glow; they are entirely unlike any other gem.
Before the creation of cultured pearls in the early 1900s, natural pearls were so rare and expensive that they were reserved almost exclusively for the noble and very rich, with a natural spherical pearl necklace evenly matched in size considered a treasure of almost incomparable value.
It is believed that pearls were first discovered by people searching for food along the seashore. With a long and ancient history, shrouded in myth and legend, we know they have been worn as an adornment since as early as 420BC. The pearl was a symbol of purity of the wearer in ancient China, while knights in the Dark Ages wore pearls on the battlefields, believing they would keep them safe. Legend has it, that Cleopatra crushed a pearl into a glass of wine to prove to Marc Antony that she could give the most expensive dinner in history.
Since Roman times, pearls have been an important commodity. With an escalating demand for pearls in Western Europe from nobility and royalty, by the 19th Century the demand for pearl jewellery became so high that oyster supplies began to dwindle.
Unlike gemstones or precious metals that must be mined from the earth, pearls are grown by live oysters far below the surface of the sea. The most valuable pearls occur spontaneously in the wild and are extremely rare. Quite by accident, a pearl is formed when a foreign object or irritant (a parasite or piece of shell) becomes embedded in an oyster’s soft inner body. The oyster takes defensive action, causing it to secrete a smooth hard crystalline substance called nacre (calcite and aragonite) to build up around the irritant, depositing it in concentric layers until a lustrous pearl is formed. The nacre is composed of microscopic crystals aligned perfectly with one another so that the light passing along the crystals is reflected and refracted to produce a rainbow of light and colour. The scarcity of natural pearls is reflected in the prices they fetch at auction.
Historically, divers risked their lives going to depths of up to 100 feet to retrieve oysters, a dangerous pursuit that would only harvest very small quantities of quality pearls. Today, cultured pearls are formed via the same process; however, the irritant is implanted in the oyster with surgical precision rather than by chance, adding a spherical bead (often mother of pearl) as a nucleus, along with a piece of mantle tissue from another oyster. The nucleated oyster is then returned to the sea, in a nutrient rich, sheltered bay to feed and grow and remain cared for by technicians. Pearls can be found, or cultivated, in both fresh water and salt water, and trade names of cultured pearls are Akoya, white or golden South Sea and black Tahitian.
In the late 1800’s Kokichi Mikimoto created the world’s first cultured pearl by manually introducing an irritant into an Akoya oyster and thus stimulating it to form a pearl. The introduction of cultured pearls caused a significant decrease in the value of natural pearls in the early 1900s. By the 1930s there were over 300 pearl farms established in Japan, producing 10 million cultured pearls with the exact same properties as those from the deep sea beds, the only difference being they had been given a helping hand at getting the process started.
Non-symmetrical pearls and irregularly shaped pearls are known as ‘Baroque’ pearls. The quality of a pearl is determined by several criteria, including its shape, size, colour and lustre. The unique lustre of pearls depends upon the reflection, refraction and diffraction of light from the translucent layers. A finer lustre is a consequence of numerous thinner layers of nacre. Gem quality pearls are nacreous and iridescent with blemish free skins.
Ranging from pure white to dramatic black, and from perfectly round to perfectly imperfect baroque, each having a wonderful iridescent shimmer, pearls are a delightful and classic addition to a jewellery collection.
JULIE FOSTER / Head of Jewels