Shells are found in a small water pool, and colorful pearls are collected after opening mussels

Scientists hope to bring endangered freshwater mussels back from the brink, State News

When the river falls, the shells are exposed, and the golden pearls are taken out.

Materiom : Mussel shells [Mytilus edulis]

Freshwater Mussels Missouri Department of Conservation

Impact of Culture Period on Quality of Image Pearls Produced by the Freshwater Mussel, Lamellidens marginalis, in Bangladesh

Wild Pearl Hunter

Biologists Investigate Mass Die-Off Of Freshwater Mussels : NPR

Wild Pearl Hunter

Freshwater pearls: river beauties that come in many shapes and colors