Colour and Lustre
Cultured pearls, like natural pearls, are found in a variety of sizes, shapes, lustres, colours and surfaces - the qualities that constitute the five criteria by which pearls should be appraised. For instance, a pearl may be of exquisite colour, yet somewhat lacking in lustre, or well shaped but leaving something to be desired in its purity of colour. For this reason, pearls that score highly in all five sectors are the most prized, and therefore the most costly.
The most important value point in pearls of equal size is lustre because it is this that gives a pearl its beauty. You should not confuse surface shine with the deep-seated glow of genuine lustre. Colour should be pure and clear and should vary from rose pink to white or cream. So-called black pearls actually, in reality, dark grey or gunmetal coloured are often dyed but nevertheless effective in mixing, for example in necklaces, to provide colour and contrast. South Seas pearls, which come from the much bigger oysters of Tahiti, are generally larger and more costly than the Akoya pearls of Japan. Some of these pearls are naturally black.Pearl necklaces are classified into graduated and uniform types. In the former, pearls of various sizes are strung together so as to taper towards the end, with the central pearls measuring about 7mm in diameter and those at the end about 3mm. Single strand necklaces are generally 40-45cm long, depending on whether they are strung knotted or plain - that is with or without knots between each pearl.
Matinee and Opera
The basic uniform pearl necklace is a single strand of pearls, which, if strung plain is about 40cm long and if strung knotted is about 45cm long, clasp included. A uniform necklace can consist of one or more strands. Both single-row and multiple-row necklaces can be any length from 40 to 60cm. The latter are referred to as matinee length.
The longest, 80cm or longer, are known as opera length or ropes. The choker can be multi-row, but is more usually a three row pearl necklace, generally 34cm long, but it differs from a standard necklace in that it hugs the neck closely.
In earrings, pearls are generally mounted as drops, studs or clusters. Mabé pearls, from Lake Mabé in Japan, which are grown against the oyster's shell, are especially beautiful when set in earrings. Cultured pearls are fashion's favourite jewels because they go so well with all types of apparel, from daywear to eveningwear. One of their most wonderful attributes is that they focus attention on the wearer, not themselves. They pick up and reflect adjacent colours and spread their soft, warm glow over the neck and wrists.
Pearls should be kept free from cosmetics, perspiration, dust and dirt. They should be stored in a soft bag away from sharp-edged jewellery and washed gently in soapy water to preserve their glow. All necklaces should be restrung at least every two years as perspiration and perfume tend to discolour the pearls and weaken the silk thread on which they are strung.