Hmmm. It never occurred to me before your post Jazzy, but I use recycled ivory (from piano keys) in my shop all the time, mostly for inlay or shims. Dad and I have made at least a half-dozen banjos completely inlaid from it, at least one of which is in Japan. Got this buddy who does piano tuning and repair... every so often he just hands me a bag of the stuff. No idea how I'd ever prove that.