They may be banded with lighter and darker shades in juveniles and the occasional individual sea urchin is completely white.

[3] Diadema savignyi can be distinguished by the fact that it has iridescent green or blue lines in the interambulacral areas and around the periproct, a cone-shaped region surrounding the anus.

[4] The range of Diadema savignyi extends from the eastern coast of Africa and the Red Sea to French Polynesia, Hawaii, New Caledonia and northern Australia.

It is typically found on mixed sandy, rocky and coral substrates especially in areas disturbed by storms or by other natural causes.

[2] Diadema savignyi is nocturnal and tends to hide in crevices or under boulders during the day, or several individuals may huddle together in the open.