QUALITY FACTOR FIVE: SIZE

The size of a pearl is measured in millimeters, through its diameter. Pearls can be smaller than 1 millimeter in size to as large as 20 millimeters and more. The average and most popular size sold today is 7 to 7-and-a-half millimeters. Though a pearl's size is not an indicator of its quality, it will determine its price. With all other quality factors being equal, the larger the pearl, the more valuable it is. The reason is simple: it's just more difficult to grow a large high-quality pearl. Therefore, pearls that are 7 millimeters and larger will always command higher prices.