Otolith
An otolith (Ancient Greek: ὠτο-, ōto- ear + λῐ́θος, líthos, a stone), also called otoconium, statolith, or statoconium, is a calcium carbonate structure in the saccule or utricle of the inner ear, specifically in the vestibular system of vertebrates. The saccule and utricle, in turn, together make the otolith organs.