Seed Pearls Classification
Almost Any Color Usually White, Cream
Appearance, RI, birefringence blink and magnification. A "tooth test" is commonly used in which a pearl is rubbed against a tooth; if gritty, this is an indication that the surface is nacre, versus plastic and glass imitations that feel smooth.
Seed pearls are usually less than 2mm in size and found in antique jewelry. Can be freshwater or saltwater.