Mussels are larger than clams and have thicker shells. Clams have a thin, delicate shell.  Mussels are also blue-green or black in color, while clams can be white, light green, or pink.  Mussels are saltier and have a tougher texture than clams. Clams are more delicate in flavor and are often described as sweet and briny. Mussels attach themselves to rocks or other hard surfaces while clams bury themselves in mud.  Clams also have longer siphons (tubes used for sucking food and water) than mussels.