One of a number of bivalve mollusks, some of them edible, such as Mytilus edulis, found in clusters attached to rocks around the N Atlantic and American coasts. It has a blue-black shell.
Freshwater pearl mussels, such as Unio margaritiferus, are found in some North American and European rivers. Margaritifera margaritifera became a protected species in 1991 having suffered from pollution and from amateur fishers who, unlike professionals, are not able to extract the pearl without killing the mussel itself. The green-lipped mussel, found only off New Zealand, produces an extract that is used in the treatment of arthritis.
1. Black marine bivalves usually steamed in wine.
2. Marine or freshwater bivalve mollusk that lives attached to rocks etc.