The crystalline substance secreted by an oyster to form a pearl. Cleanliness of the pearl surface refers to the absence of disfiguring spots, bumps or cracks. A pearl with a clean surface will have a higher value than a spotted, bumpy or cracked one. Since cultured pearls are grown by oysters and subject to the whims of Mother Nature, it is very rare to find a perfectly round pearl. While rounder pearls are more valuable, asymmetrical, or baroque, pearls have a unique charm and are available at a more moderate cost.
Cultured pearls occur in colors from ros to black.
Generally, the larger the pearl, the more valuable it will be. Caring for Your Pearls Pearls are more delicate than other gemstones and precious metals, needing special care to ensure they will remain clean, bright and lustrous for years to come. Pearls should be put on after the application of makeup, perfume or hair spray. After they are worn, a soft, damp cloth may be used to wipe them free of any of these harmful elements. Cultured pearls should be washed periodically with a mild soap.