The shell is large, thick and heavy, with a roughly circular outline, which is interrupted by the nearly flat hingeline. On the outside of the valve it is covered with strong, flat ribs which are crossed by many fine lines. These can be nearly rubbed off on the tops of the ribs. The outer colour is off-white to pale yellow or pinkish brown and can be marked with reddish brown or purple. Internally they are bright white some with patches of brown or purple.
At or just below the surface of coarse sand or fine gravel. Can be found in large dense beds often with Purple Cockles.
Coastal Marine Inverts Vol 1