Pearl size chart

The image below shows the scale of pearls in ascending millimeter sizes from 5mm up to 10mm against the proportion of a U.S. dime. 

Pearl necklace size chart

 

See image below for Freshwater size as compared to US Dime

Freshwater Pearl Size Chart

See image below for Tahitian Pearl size as compared to US Dime

Tahitian Pearl Size Chart

See image below for South Sea Pearl size as compared to US Dime

Golden South Sea Pearl Size Chart