How is a cultured blister pearl formed?

A cultured blister pearl is formed when a nucleus, which is often a bead or piece of tissue, is intentionally inserted into a mollusk, specifically under the mantle tissue, which is situated inside the shell. This process is part of pearl cultivation, where human intervention stimulates the mollusk to produce nacre, the material that forms the pearl, around the nucleus.

The unique characteristic of a blister pearl is its attachment to the shell of the mollusk, making it different from traditional round pearls that are formed completely within the mollusk’s body. In the case of a blister pearl, the development occurs partially within the shell, resulting in a shape that is often flat or irregular, yet it retains the same nacre quality that is present in other cultured pearls.

Understanding this formation process highlights the role of human intervention in creating cultured pearls, distinguishing them from natural pearls, which form spontaneously without any inserted nucleus or interference from humans.