Interestingly, I have a fairly large number of whales teeth, and a bit of whalebone. The teeth are essentially identical to ivory. This was all acquired by my parents in the early ‘70s before the embargo on whale products. At this point, it is virtually impossible to sell this stuff across state lines, even though the animals died long ago and the product was brought legally into the country. But you know, I’m pretty sure that I can find someone somewhere in Texas who does artwork with handgun grips to carve some of those teeth up and put it on some of my handguns.
The big ivory legal source now is fossil ivory from mammoth tusks found in Alaskan and Siberian permafrost. The source is not easy to find and much of The ivory is not usable due to rot but enough is available to keep the market alive.