photo courtesy of Pearl-Guide

The shape of the nucleus in a cultured pearl can influence and sometimes change the final shape of the pearl, but the transformation depends on a few factors involving the biological processes inside the mollusk.

Cultured pearls typically begin with a globe like bead nucleus, usually made from shell. The mollusk coats the nucleus with layers of nacre. If the nuceus is not perfectly round the pearl may reflect that shape.

Sometimes the nucleus can shift or rotate inside the mollusk. If it moves irregularly or becomes tilted, nacre may be deposited unevenly. This can result in a Baroque or off round pearl.

If the mollusk reacts to the nucleus in a defensive way, it might wrap the nucleus asymmetrically in nacre that can result in unique shapes.

Sometimes biological interruptions during the pearl development can cause dents, rings or lobes that change the outer form of the pearl.

And then there are the intentional shapes of nucleus that will cause the nacre to develop in unusual shapes. You will have seen coin, heart, or even buddhas used! Buddha pearls are a tradition that goes back to the 1300s.