The smallest and most abundant of the giant clams. The shell is white in colour on the Great Barrier Reef, though in parts of Asia it may be pinkish-orange to yellow on both the inside and outside of the shell. This species has a very distinct triangular ovate shell (from a side view) with closely spaced scales near the shell edge, and a very wide byssal orifice. The byssal attachment is strong and the clam burrows into the coral substrate, with only the mantle and the top edge of the shell protruding. Mantle colour is variable, but most commonly a dark blue-brown. Distinguished from other species of Tridacna by the small size and deeply embedded habit.