Pearls were most commonly used in earrings. The best pearls came from India and have a hardness between 2.5 and 3.5. Below is a photograph of two modern strands of pearls and a modern ring. To be set in rings, pearls have to have a pin stuck in the center and the glue or some other adhesive poured around the pin to hold the pearl in place. Pearls are measured in millimeters when they are found, and they are categorized according to size and color.
Pearls come in many colors, black, blue, yellow, pink, white, and many shades in between.