Freshwater pearl sizes normally range from 5mm to 12mm, although some larger sizes can be found occasionally. The freshwater pearl size below 7mm is considered small, while sizes ranging from 7mm to 9mm are more popular for necklaces. The freshwater pearl size above 10mm is considered rare and more valuable. The larger the freshwater pearl the more difficult it becomes to find a perfectly round shape.
South Sea Pearls
South Sea Pearls dominate the pearl world in size and demand. They are usually found between 9mm and 15mm in size. Sometimes South Sea Pearls can be found in excess of 20mm, which is extremely rare. South Sea pearls below 10mm are considered small in size. 10mm to 12mm size is more popular for necklaces while size above 13mm is considered rare and more valuable.
Japanese Akoya Pearl Size
Japanese Akoya Pearls range from as small as 3mm to as large as 9.5mm. Akoya Pearls below 7mm are considered small in size. 7mm to 8mm are more popular sizes for necklaces while Akoya pearl size above 8mm are considered rare, more valuable, and higher in quality.
Tahitian Pearl Size
Tahitian pearl size generally ranges from as small as 8mm to as large as 16mm. Tahitian pearl below 10mm is considered small in size. Pearl sizes ranges from 10mm to 12mm and are more popular for necklaces, while size above 13mm is considered rare, more valuable.
Pearl Shapes are a significant factor in determining value. The most common shapes are irregular or baroque. A pearl’s shape has no effect on quality, but certain shapes are much rarer.
The rarest and most desirable shape among pearls is the perfect round.
Shapes in order of rarity and price (other factors being equal):
- Teardrop (pendant) Button