A pearl is formed when a small object, typically a parasite or piece of organic matter, becomes embedded in the tissue of an oyster or mollusk. In response, the mantle tissue of the mollusk secretes nacre. As the nacre builds up in layers, it surrounds the irritant and eventually forms a pearl. It is a myth that a grain of sand can cause a pearl to form, as nacre will not adhere to inorganic substances.

       There are three main types of pearls: cultured, natural and imitation. Natural pearls are pearls that are created more or less without any human intervention, and are very rare. Cultured pearls are created by an oyster, but the pearls growth is stimulated by implanting a foriegn object into the tissue of an oyster or mollusk. Imitation pearls are not created by an oyster, but are usually glass or some other man-made material coated to create the illusion of a pearls lustre.

There are five main factors that go into gauging the value of a Pearl: Lustre, Surface, Shape, Color and Size.

Lustre: This is the way a pearl reflects light. Pearls with low lustre appear yellow, chalky or dull rather than shiny.


Surface: The absence of disfiguring spots, bumps or cracks on the surface of a pearl tend to make it more desirable. The cleaner the surface of the pearl, the more valuable.


Shape: It is very rare to find a perfectly round pearl, but the rounder the pearl, the more valuable it is. Baroque pearls, which are asymmetrical in shape, can still be lustrous and appealing, and they often cost less than round pearls.


Color: Cultured pearls come in a variety of colors from rose to black. While the color of a pearl is really a matter of the wearer’s preference, usually rose or silver/white pearls tend to look best on fair skins while cream and gold toned pearls are flattering to darker complexions.


Size: Cultured pearls are measured by their diameter in millimeters. They can be smaller than one millimeter in the case of tiny seed pearls, or as large as twenty millimeters for a big South Sea pearl. The average sized pearl sold today is between 7 and 7-1/2 millimeters.

       There's no gemstone quite like the pearl. Treasured throughout the ages, pearls are now more readily available than ever before. There are four main categories of pearls: Akoya, Freshwater, South Sea, and Tahitian.

       Japanese Akoya pearls are still considered among the best pearls in the world. Fine Japanese Akoya pearls are rounder than most other pearls and possess very high luster. Born of the saltwater oyster Pinctada fucata, Akoya pearls are produced in sizes from 3mm-10mm, in round, symmetrical and baroque shapes. Akoya pearls are also grown in China. For the past decade, Chinese pearl farmers have made great strides in their pearl culturing techniques.

       Other saltwater varieties are produced in the South Pacific; Australia, Indonesia and the Philippines grow large white, cream and golden South Sea pearls in 10mm-16mm sizes, sometimes reaching 20mm. Born of the saltwater oyster Pinctada maxima, these South Sea beauties are among the world's largest and most lustrous pearls.They are produced in round, semi-round, circle, drop, oval, button and baroque shapes.

       Tahiti, the Cook Islands and various other areas of French Polynesia produce black South Sea pearls, which are all referred to as Tahitian pearls. Born in the black-lipped saltwater oyster Pinctada margaritifera, these naturally colored black beauties are produced in sizes from 8mm to 14mm, sometimes reaching 20mm, in various shapes. They range in tones from gray and blue-gray to brown-black and greenish black. The most expensive color is black with an iridescent peacock-green overtone.

       Freshwater pearls are also causing quite a stir on today's market. China is the largest cultivator of freshwater pearls in 3mm - 10mm sizes and baroque to round shapes. Born of the freshwater mussel Uniondae hyriopsis schlegeli, these gems come in a spice rack of natural colors including plum, lavender, peach, apricot, curry, red pepper, cinnamon, celery and sage. They are durable, have a thick nacre and nice luster and come in colors not naturally found in any other pearl type, for very affordable prices.

       Cultured pearls are relatively soft compared to other gemstones and precious metals. So it is important to take special care of your pearls to ensure they will remain bright and beautiful for generations to come.

 

       Cosmetics, perfume and hair spray all contain chemicals that can dull the luster of a pearl over extended periods of time. Even acids contained in body oils and perspiration can work to damage luster in the same way


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  Therefore, it is best to put your pearls on after applying makeup, perfume and hair spray. Wiping the pearls with a soft damp cloth after you wear them will ensure that they remain free from any harmful buildups of these compounds. Periodically, the pearls should be washed with a mild soap.

Try to keep your pearls separated from hard jewelry items, such as metals and other gemstones, to prevent them from scratching your pearls. Pearls are best kept in a soft cloth pouch or a separately lined jewelry box.