Chondria coerulescens is a red alga belonging to the family Rhodomelaceae. The thallus is cartilaginous, flexible, cylindrical, 4.5 x 6 cm, with thin branches arranged in an irregular spiral and with sparse branching up to three orders. It is yellowish to bluish in colour with turquoise iridescence on young axes and black when dry. It lives on rocks or muddy gravel in shallow intertidal and subtidal areas of the Atlantic and Mediterranean. The blue sheen is due to the structural coloration of the fronds while they are alive.