Elephant and Mammoth ivory
Elephant and mammoth tusk ivory comes from the two modified upper incisors of extant and extinct members of the same order (Proboscidea). African and Asian elephants are both extant. Mammoths have been extinct for 10,000 years. Because of the geographical range in Alaska and Siberia, Mammuthus primigenus tusks have been well preserved. Therefore, Mammuthus primigenus is the only extinct proboscidan which consistently provides high quality, carvable ivory.
An African elephant tusk can grow to 3.5 meters in length. Enamel is only present in the tusk tip in young animals. It is soon worn off and not replaced. Whole cross-sections of proboscidean tusks are rounded or oval. Dentine composes 95% of the tusk and will sometimes display broad concentric bands. Cementum, which can be thick in extinct genera, covers the outside of the tusk. Cementum can present a layered appearance, particularly in mammoth.
Polished cross-sections of elephant and mammoth ivory dentine display uniquely characteristic concave angles and convex angles. Concave angles have slightly concave sides and open to the medial (inner) area of the tusk. Convex angles have somewhat convex sides and open to the lateral (outer) area of the tusk. Outer Schreger angles, both concave and convex, are acute in extinct proboscidea and obtuse in extant proboscidea.
