Pearls have long been considered to be among the most splendid of gems in many countries and cultures.
Natural pearls are made by oysters and other mollusks. Cultured pearls also are grown by mollusks, but with human intervention; that is, an irritant introduced into the shells causes a pearl to grow. Imitation or simulated pearls are man made with glass, plastic or organic materials.
Because natural pearls are very rare, most pearls used in jewellery today are either cultured or imitation pearls. Cultured pearls, because they are made by oysters or mollusks, usually are more expensive that imitation pearls. A cultured pearl's value is largely based on it's size, usually stated in millimeters, and the quality of its nacre coating, which give it luster. It is more difficult for oysters to grow large pearls, and hence they are more scarce. However, two pearls of similar size may be valued differently if one is superior in Orient. Orient is the deep inner glow and shimmering iridescent characteristics of sea-grown pearls - the deeper the luster and iridescence, the more precious the pearl.
Found in a variety of shapes and colours, the types of pearls include:
Akoya Pearls: A speciality of Japanese pearl farms, Akoya pearls are one of the most popular. A high quality pearl, they are known for their lovely orient and warm colour.
Freshwater Pearls: As the name suggests, freshwater pearls are found in fresh water lakes and rivers - cultivated in mollusks not oysters. They are generally elongated in shape and have milky translucent appearance. Most freshwater pearls come from China, and are the product of an elaborate process in which a single resilient mussel can be harvested many times, yielding several pearls at a time.
South Sea Pearls: South Sea cultured pearls are exceptional quality pearls with a whitish, almost silver colour. Much larger that the average pearl, the smoothness and roundness of these pearls are exceptional. South Sea pearls come from the white-lipped variety of the pinctada maxima oyster. This oyster is much larger than the oysters that produce Akoya and Freshwater pearls, so the pearl that it produces is much larger as well. Because of the rarity and sensitivity of this type of oyster, cultivation of these pearls is much more difficult, making them more expensive.
Considerations when buying Pearls:
Look for luster and orient in the shadow area of the pearl, not in the area where the light is shining. Colour tones should be clear, not dull or muddy. Look out for cracks, chips or disfiguring blemishes.
Pearls in a strand should blend well - particularly in regards to luster, orient and colour. Roll a strand of pearls along a flat surface to determine if all pearls are strung through their exact centers - all of them should roll evenly without a noticeable wobble.