Typical sizes by type
| Pearl | Typical size (GIA) |
|---|---|
| Freshwater pearls | 6 to 12 mm (Edison pearls 11 to 16 mm or more) |
| Akoya pearls | 6 to 9 mm; over 9 mm is larger and rarer |
| Tahitian pearls | 8 to 14 mm; over 14 mm is less common |
| South Sea pearls | 8 to 18 mm |
| Golden South Sea pearls | 8 to 18 mm |
| Edison pearls | About 11 to 16 mm or more |
| Soufflé pearls | 16 to 23 mm |
| Kasumiga pearls | Typically 11 to 15 mm; some over 16 mm |
| Sea of Cortez pearls | About 7 to 11 mm (2001 to 2002 harvests) |
Cultured pearls overall range from about 2 to 16 mm, with South Sea pearls reaching 18 mm or more (GIA).
How pearls are measured
- Round and near-round: diameter in millimeters.
- Other shapes: length and width (GIA).
- Strands: usually given as a range, such as 7 to 7.5 mm, because pearls in a strand vary slightly.
How many pearls in a strand?
A rough guide: divide the strand length in millimeters by the pearl size. An 18 inch strand is about 457 mm, so 7 mm pearls make about 65 pearls before knots and the clasp. The necklace length tool does this for you.
