The importation of raw African elephant ivory to the United States has been illegal since 1989, and the trade of elephant ivory within the U.S. is heavily regulated. Because of this, it can be difficult to obtain authentic carvings, jewelry or other ivory pieces. The market is filled with replicas that may be made of resin, plastic, bone or non-elephant ivory. Though walrus tusks and teeth, hippopotamus tusks and teeth, narwhal tusks and whale teeth and are all considered ivory, elephant or mammoth ivory is usually regarded as "true ivory" and is more desirable than other types.
Examine all sides and the bottom of your piece for a pattern that looks like woodgrain. This pattern is typical of ivory but may or may not be obvious depending on how the piece was cut or carved. Look for color that varies slightly, from creamy white to a yellow-tan or yellow-brown. Bone and plastic reproductions will have no color variation or the variation will be extreme.
Test for faux ivory. Dip a Q-tip in alcohol and rub it on an inconspicuous area to test for paint or varnish being used to give fake ivory an aged look. If your piece has been painted or varnished, it will come off on the Q-tip.
Check the authenticity of ivory using a U.V. light source. Ivory will glow bright-white under ultraviolet light whereas resin or plastics will absorb the light and appear dull.
Determine the type of ivory by examining your piece under a 10x or higher magnifier. Ivory from elephant or mammoth tusks will have fine lines on the surface called "Schreger lines" that form a cross-hatch or diamond pattern. Measure the angles of the Schreger lines with a protractor. Angles less than 90 degrees indicate mammoth ivory; angles above 115 degrees show evidence of elephant ivory. Minuscule circular or oval pits instead of lines indicate your piece is probably bone.
Conduct a "pin test." Heat the end of a pin over a candle or lighter until it is red-hot. Select an inconspicuous spot and press the pin against the surface of the piece. Ivory will be largely unaffected by the pin test, but the hot pin will damage the surface of resin or plastic, producing a melting-plastic smell.