Which term refers to a pearl formed through natural processes?

The term that describes a pearl formed through natural processes is "natural pearl." Natural pearls develop when an irritant, such as a grain of sand, enters the shell of a mollusk. In response to this irritant, the mollusk secretes layers of nacre (the same substance that forms the inner layer of its shell) around the irritant, gradually building up a pearl over time. This process occurs without human intervention, making these pearls unique and often highly valued due to their rarity.

The other terms listed refer to different types of pearls that involve human interaction or specific processes. Artificial pearls are created entirely by human means, often using plastic or glass materials to mimic the appearance of natural pearls. Synthetic pearls, on the other hand, are laboratory-created and have the same chemical composition as natural pearls but do not form in nature. Enhanced pearls can include natural pearls that have undergone treatments to improve their appearance, such as dyeing or bleaching. These distinctions highlight the uniqueness and value associated with natural pearls compared to other types.