title: Hard as rocks.
mesh_terms: D001482:Base Composition; D001842:Bone and Bones / Q000002:abnormalities*; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D000013:Congenital Abnormalities / Q000235:genetics; D003743:Dental Enamel / Q000002:abnormalities*; D006801:Humans; D009154:Mutation / Q000235:genetics; D013577:Syndrome; D014071:Tooth Abnormalities / Q000235:genetics