This large mussel is found attached to rock by a byssus. It is variable in colour, from a mostly black tinged with red, to a rusty red or purple colour and very pale gold towards the base of the shell. It often develops stiff hair-like tufts over the larger end-half of the shell. It can be difficult to distinguish the various species of mussel, but this species can be identified by its colouration, lack of ribbing and relatively large size.
