Pearl size refers to the pearl’s diameter, which is measured in millimeters. Normally, the larger the pearl, the more rare it is and the more valuable. Keep in mind that pearl strands also have a length, which also affects price because of the number of pearls needed to create that particular necklace length.
The size of the oyster directly affects the size of the pearl it creates. Larger mollusks, for instance, create larger pearls.
However, large cultured pearls require a larger nucleus to be implanted into the oyster — which increases the …