This is an immaculately stabilized piece of Siberian woolly mammoth ivory (Mammuthus primigenius). The ivory is rock-solid and completely dry. This piece will not crack even if you cut across or along the crack.
One cross-cut section is slightly thicker and wider than the other. Please carefully look at the pictures for precise dimensions. The colour of the ivory is white.
Geological epoch: Pleistocene.
Age: Over 10,000 years.
Origin: Sakha Republic (Yakutia).