Rolan and Luque (1994) state that the exterior and interior of T. nitida shells in Ria de Vigo are violet, and Jeffreys (1867) states that its shell is purplish, with brighter purple lines than on T. reticulata. But, the presence and intensity of purple varies greatly, is often absent or, on beachworn shells, faded, see fig. 60. Few have such intense purple as in the image above.

Albania, Adriatic. © A. Golemaj.