Pearl Size:
Pearl Size/Weight - The Bigger the Better
With all other quality factors being equal, as pearls get larger they get more expensive. This is because it is very difficult for an mollusk to grow a pearl larger than 5mm. The bigger the mollusk, the bigger the bead it can accept and the bigger the pearl it can grow. The Japanese mollusk measures approximately 4 inches in diameter. It produces smaller pearls then the silver or gold-lip mollusk which can measure up to 12 inches across. Pearls are measured in millimeters. When measuring spherical pearls, you measure the diameter. They can range from smaller than one millimeter to as large as 20 millimeters. Pearls of other shapes are measured by the length and width. The most common unit of weight at the retail level is the gram. Pearls are also sold by the strand.
South Sea Pearls
- Australian South Sea pearls, are very rare. They are the largest and because of this they are the most expensive pearls in the world. Only the South Sea’s Mother of Pearl Shell can create quality pearls of such a size. Measuring across the smallest diameter, their size can run from 9mm to an extremely rare 18 mm. Baroque South Sea pearls can grow even larger.
Black Pearls
- Black pearls can range in size from about 9mm to 18mm with their average size tending to be between 9 and 11.5 mm. There have been black pearls measuring 25 to 30 mm. A 1 mm increase in the size of medium quality pearls can raise their price 100% to 200%
Freshwater Pearls
- Chinese freshwater pearls are now available in sizes 10mm to 13mm.
