Ivory is traditionally thought of as simply elephant tusk, but it's more than that, notes Bobby Mann, co-founder of the International Ivory Society. Ivory encompasses a full range of teeth and tusks of mammals including elephant, mammoth, walrus, hippopotamus, sperm whale, narwhal, wart hog, and boar. Natural ivory substitutes include bone, antler, horn, nuts, and hornbill. Mann, an ivory identification expert who speaks frequently on the topic, gave a two-day presentation and workshop at the recent National Association of Jewelry Appraisers conference in Annapolis, Md. You can identify ivory by shining long-wave ultraviolet light on it; new ivory will glow white. As material patinates, the whiteness of the fluorescence will dull. All manufactured substitutes will absorb the UV and appear dull. Bench tips. "Ivory polishes up very nicely using just the plain old tripoli and rouge,"