LOT 496: Hamilton & Inches. A cultured South Sea and Tahitian pearl and diamond suite
Estimate: £15,000 - £25,000
History and origin
The history of pearls can be traced back to ancient times, and have captivated civilisations such as the Persians, Chinese, Egyptians, Greeks and Romans. The world’s oldest pearl, the Abu Dhabi Pearl, dates back 8,000 years to the Neolithic period and was discovered as late as 2017 on Marawah Island, off the coast of Abu Dhabi. Pearls were worn as Jewellery by the Romans and commanded extremely high prices, and they were also highly prized in Europe - Queen Elizabeth I of England had her robes covered with pearls which had to be removed when cleaned! During the Renaissance large misshapen pearls were often utilized to form the body of a person or animal when made into Jewellery, such as the famous Canning Jewel in which the pearl forms the torso of a Merman and is mounted with gold, diamonds and gems.
The word pearl comes from the French Perle which in turn originated from the Latin Perna meaning ‘sea mussel’. The scientific name Margaritiferidae originates from the Persian word Margarita, meaning highly valuable.
Types of pearls natural, cultured and simulants
The identification of pearls is often confusing to the lay person. For centuries only natural or imitations were encountered. In the late 19th and early 20th century researchers in Japan lead by Kokichi Mikimoto pioneered the technique of inducing oysters to produce pearls on demand. Natural pearls are caused by a fine irritant which has entered the oysters soft tissue mantle. This stimulates the oyster to produce a pearl by releasing nacre to cover the irritant and protect the oyster from damage. To create a man induced or cultured pearl, a small bead of mother of pearl or other material is inserted into the mantel to artificially stimulate the oyster into producing nacre around the bead to form a pearl. Cultured pearls grow more rapidly than natural pearls.
The highest value pearls are those coming from salt water conditions. Another type of pearl is the less valuable freshwater pearl coming from bivalve mussels that live in lakes and rivers. Perhaps the best known are those from the Mississippi which have an appealing elongated lustrous appearance and are often used as drops for pendants etc. These can also be cultured and are not of high value. A domed mabé or blister pearl is formed on the inside of the shell of the oyster either naturally or cultured which can be produced as a half sphere often used in earrings.
LOT 523: A French Belle Époque platinum and seed pearl flexible necklace
Identification and value
The difference in value of natural/oriental and cultured pearls is significant. Natural pearls are rarer and command high prices. To differentiate accurately between the two, they must be X rayed under laboratory conditions. Preliminary visual examination can be a good pointer. Natural pearls are very rarely completely spherical and can vary in shape and are commonly cushion or barrel shaped, often with flattened ends. They will generally vary in tone which is often quite subtle. As they are made up almost entirely of calcium carbonate/nacre they will be heavier in the hand than that of their cultured counter parts. Surfaces will also vary and under examination under 10x magnification subtle differences can be seen. Pearl simulants such as those made of plastic or glass can be easily identified. Large round pearls ranging from 8mm to 15mm in diameter will almost certainly be those cultured pearls farmed on the Western Australian coast or Tahiti.
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