Elephant and mammoth ivory
- Elephant and mammoth ivory
-
Mammoth Ivory tusk carved by Japanese Master carver
Elephant and mammoth tusk ivory comes from the two modified upper incisors of extant and extinct members of the order Proboscidea. Mammoths are believed to have been extinct for 10,000 years. Because of the geographical range in Alaska and Siberia, Mammuthus primigenius tusks have been well preserved. Therefore, Mammuthus primigenius is the only extinct proboscidan which consistently provides high quality, carvable ivory.
An African elephant tusk can grow to 3.5 metres 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 Schreger lines. Schreger lines are commonly referred to as cross-hatchings, engine turnings, or stacked chevrons. Schreger lines can be divided into two categories. The easily seen lines which are closest to the cementum are the outer Schreger lines. The faintly discernible lines found around the tusk nerve or pulp cavities are the inner Schreger lines. The intersections of Schreger lines form angles. These Schreger angles appear in two forms: 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.[1]
Mammoth Ivory tusk carved by Japanese Master carver
See also
References
External links
Wikimedia Foundation.
2010.
Look at other dictionaries:
Ivory — is formed from dentine and constitutes the bulk of the teeth and tusks of animals such as the elephant, hippopotamus, walrus, mammoth and narwhal.The word ivory was traditionally applied to the tusks of elephants; the word is ultimately from… … Wikipedia
Ivory (disambiguation) — Ivory is a hard, white, organic substance that is the bulk of the teeth and tusks of animals such as the elephant, hippopotamus, walrus, mammoth, and narwhal. Ivory may also refer to:Places* Côte d Ivoire (Ivory Coast), a country in West Africa * … Wikipedia
Mammoth — For other uses, see Mammoth (disambiguation). Life Mammoth Temporal range: Early Pliocene to Middle Holocene … Wikipedia
Elephant — Taxobox name = Elephant image width = 250px image caption = An African Bush Elephant near the border of the Serengeti and Ngorongoro Conservation Area in Tanzania. regnum = Animalia phylum = Chordata subphylum = Vertebrata classis = Mammalia ordo … Wikipedia
ivory carving — Carving of ivory into decorative or utilitarian objects. It has flourished since prehistoric times. Most Stone Age carvings have been found in southern France, in the forms of small nude female figures and animals. A masterpiece of early Egyptian … Universalium
Ivory carving — by using sharp cutting tools, either mechanically or manually.Humans have ornamentally carved ivory since prehistoric times, and much of the prehistoric work reveals information about the use of tools during the carving s time period. The ivory… … Wikipedia
mammoth — /mam euhth/, n. 1. any large, elephantlike mammal of the extinct genus Mammuthus, from the Pleistocene Epoch, having hairy skin and ridged molar teeth. adj. 2. immensely large; huge; enormous: a mammoth organization. [1690 1700; < Russ mam(m)ot… … Universalium
ivory — n. (pl. ies) 1 a hard creamy white substance composing the main part of the tusks of an elephant, hippopotamus, walrus, and narwhal. 2 the colour of this. 3 (usu. in pl.) a an article made of ivory. b sl. anything made of or resembling ivory, esp … Useful english dictionary
elephant — /ˈɛləfənt / (say eluhfuhnt) noun 1. either of two very large, herbivorous mammals of the family Elephantidae, the Loxodonta africana of Africa (African elephant) and the somewhat smaller Elephas maximus of India and neighbouring regions (Indian… …
Conservation of ivory — Ivory carving is a decorative art or craft practised since prehistoric times. Its conservation is concerned particularly with the environmental causes of deterioration. Contents 1 Ivory 2 Deterioration 3 Technical examination … Wikipedia