Grafting is the process of inserting a small nucleus into the mature pinctada margaritifera oyster in the hope of producing a pearl. Successful grafting requires a unique combination of ideal conditions: the appropriate lagoon environment, a well prepared and healthy receiving oyster, a donor mollusk that produces a quality nucleus, and an expert grafter.
The nucleus is a white bead usually obtained from a freshwater bivalve native to the Mississippi River, the legumia recta. The size of the nucleus will determine the size of the future pearl. Insertion of the nucleus stimulates an immune response in the pinctada margaritifera oyster, causing it to secrete a substance known as “nacre” that coats the nucleus.
Approximately 40 days after grafting, the grafts are checked to determine the degree of success of the operation.