This is a short section of walrus ivory. Note the indent running the length of the piece. This is a usual feature found on the inner portion of the tusk nearest to the animal. In noting a slight tapering on the right side, this is suggestive for this piece to be one of a left walrus tusk.
When viewing the cross-section of the walrus tusk, three layers are visible. There is the outer cementum, in the middle there is the primary dentin, and at the center, the secondary dentin. This inner layer is often noted to have a “grapey” appearance.
When creating tools, such as harpoon heads or drills, the best portion of the ivory to use is the primary dentin. This is the least brittle and most uniformly structured portion of the tusk.
In cross-section, walrus ivory can be easily distinguished against mammoth ivory by the presence of Schreger Lines in the mammoth ivory. These are “V” shaped lines which appear at 90 degrees or less in mammoths, and greater than 115 degrees in modern elephants.
Mammoth ivory in cross-section:
Modern elephant ivory in cross-section: