The Size of a Pearl
A round pearl is measured across its diameter in millimetres.
For non-spherical, baroque and other shapes of pearls, both the length and width of the pearl is measured.
The most popular Akoya and Freshwater pearl sizes for earrings and necklaces are between 7 and 9mm in diameter.
South Sea and Tahitian pearls are typically worn between 9 and 11mm in diameter, or larger for more statement pieces.