Fossil Ivory + Tooth
Fossil ivory is found all over the world and includes Wooly Mammoth, Mastodon, and Walrus. Unlike most other prehistoric animals, their remains are often not literally fossilized - that is, turned into stone - but rather are preserved in their organic state, and is actually best described as ancient ivory. This is due in part to the frozen climate of their habitats, and also to their massive size. Instead of decaying or undergoing petrification, Ivory from animals that died hundreds or even thousands of years ago often remains much as it was, though sometimes taking on coloration from surrounding minerals, this can result in intense coloration and patterns. No animals were killed to obtain this material.
Fossil walrus ivories are primarily found on St. Lawrence Island, Alaska, it weathers out of the stream beds and along the beaches. A small amount is found from the Alaskan herd, and some along the Alaskan coast. The majority of it is excavated by Eskimos from their Ancestral village sites, as a source of income. Walrus ivory is usually between 500 and 3000 years old, and generally doesn't exceed 10,000 years old. Walrus tusks were often modified for use as ice axes, by flattening a section to facilitate the attachment of a handle, then they were lost or discarded. Other examples of use include sled runners, fire starters, harpoon or spear tips, as well as decorative items such as figurines and jewelry. These artifacts, if not archaeologically significant, are often used as raw material. Ancient walrus ivory does not differ from modern ivory except in coloration. There is a hard enamel layer on the outside of the tusk, usually no more than 1/2 cm thick, then there is a layer of dentin, which does not display much of any grain. The core of the tusk is distinctively different, having a characteristic grain pattern resembling tightly compressed spheroids. Coloration is primarily from minerals in the soil... copper for the blues and greens, manganese and iron for the browns and oranges, gold for the rare reds....and seaweed in some cases.
Mammoth and Mastodon Ivory is found in the Alaskan Arctic, Canadian Yukon and Siberia for the majority of the material, though there is material also found in more places in the world than not, from China to South America, all over the U.S. and Mexico, Etc.. Fossil Mammoth ivory can come in the form of whole perfect tusks, which are often mounted as specimens. The tusks can also delaminate into long curved sheets of fairly thin material arranged concentrically around the core. Proboscidian ivory may be recognized by the grain pattern visible in a cross section, which displays a double spiral pattern, a series of clockwise spirals crossing others running counter clockwise. If one thinks of the crossings of these spirals as being the points of a star shape, ivory with acute angles at the points of the star is from modern elephants, mammoth and mastodon ivory shows obtuse angles instead. Except for an isolated herd of pygmy mammoth that died out about 3000 years ago on a Siberian island, it is all pre Ice-age; 10,000 years old to possibly a million or so years old. Coloration occurs from the same above named minerals, and anything else that could leech into the Ivory during countless cycles of thaw and freezing. The same process causes the minerals to leech into the Walrus Ivory.
Most of the Mammoth Ivory is found as a consequence of gold mining, mostly In Canada and Alaska. In Siberia it is mined for its own sake, often found in deposits after violent winter storms have revealed a portion of the material sticking up from the perma frost near ancient lake beds, and it's further excavated from there, where it as been a resource for centuries. The Russians have been industrious in developing a world market for their ivories.... the U.S, and Canada lag far behind.
The teeth of mammoths are quite distinctive, they consist of a series of compressed plates composed of enamel surrounding a dentine core. These tooth structures are held together in a matrix of cementum. These cemented plates make a very tall, strong, and wear-resistant tooth.
After a tooth erupts from the gum cavity, the mammoth uses it in grinding coarse vegetation like grass. Grass is a very hard material to eat: it has small pieces of silica (a glass-like substance) in its leaves. These pieces of silica act like sandpaper grit and would wear away a less resistant tooth very quickly. This use causes the tooth to develop a flat top with low enamel ridges where the plates have been worn. Teeth erupted from the back of the jaw and slowly moved forward as it wore to be replaced by another tooth from behind.
The unique structure of the teeth create beautiful internal patterns and surface qualities, and change depending on how the tooth is cut. The different layers make working the material difficult, but benefits include the ability to have book-matched pairs, and larger sizes and thicknesses than many other materials.