Any pearl that looks too chalky or dull indicates low quality. 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 or cracked one. Because cultured pearls are grown by oysters and subject to the whims of 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 lower cost.
Cultured pearls occur in colors from rose to black.
Measured by diameter in millimeters, generally, the larger the pearl, the more valuable it will be.