After the pearl mussel was cut open to take out the pearl, its shell almost became waste in its early years. But now they have other uses:

Grinding into powder, and molding into mother-of-pearl beads;

Directly used as an ornament made of shellfish;

In the form of mussel shells, clean them up and use them as specimens of mother-of-pearl;

Several of them are "foreign bodies" used to nest in the new mother of the most cultured pearls.