Though there a few exceptions, most ivory products can't be offered on eBay because of various international trade restrictions and treaties banning the sale of these items. You can find additional information about ivory laws below.

Restricted
Antiques that contain 5 percent or less of real ivory and were made before the year 1900–for example:
Musical instruments with ivory keys, such as a flute, a piano, or a trumpet
Furniture with ivory inlay or ivory drawer handles, such as a cabinet, a hutch, or a desk
When selling these items:
Include a picture of the item in your listing
Specify the exact year the item was made and include the info in your listing description
Bone from non-ivory–producing animals (such as bison, buffalo, and oxen) as long as the species is clearly stated in the listing description
Cultured, man-made, or vegetable ivory as long as the listing description specifies what the item is made of

Not allowed
Bone from animals that produce ivory, including elephants, mammoths, walruses, and whales
Carved and uncarved ivory
Fossilized ivory
Manufactured items with more than 5 percent of actual ivory such as:
Canes
Chess pieces
Figurines
Jewelry
Scrimshaw
Raw ivory