The major difference between the two is whether the foreign material was seeded into the shell by human hands or naturally. After the seeding process, the shellfish are carefully selected and put into the sea or fresh water through specially crafted cages. The nucleus placed inside stimulates the shell to secrete layers upon layers of nacre, thus producing pearls.

This process generally takes from one to three years, depending on the type, size, and quality of the pearl. Over time, the shells cover the pearls, allowing them to grow to larger sizes and better luster, but the condition of the shells must be constantly monitored because even the slightest change in the condition or position of the shells can distort the shape, luster, and speckles of the pearls. For this reason, the shells in the farms are constantly pulled out of the sea, cleaned, observed, and adjusted.