Looking for some ivory at the market?
Bone & Plastic are often mistaken for their more desirable counterpart ivory. To investigate authenticity, ask for a jeweller's loop, and look for striations, pores, these telltale signs for bone, and not ivory. Bone often looks similar so look carefully.
Ivory has a higher burn point, so it you get a needle red hot, bone and plastic will singe, ivory will not. This is the tried and true tested way to check its authenticity. When you're holding it, look for rings of growth, much like a tree, and check its weight. Plastic is a lot lighter than ivory.
One thing to make note of though, ivory is often artificially aged with tea. See if a bit of a spit polish with wear off anything when you look for these fake aging techniques.