An otolith (οτο-, oto-, ear + λιθος, lithos, a stone), also called statoconium or otoconium or statolith, is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. They have been identified in both extinct and extant vertebrates. Counting the annual growth rings on the otoliths is a common technique in estimating the age of fish. The saccule and utricle, in turn, together make the otolith organs.