My apologies to all, especially atlatl, for my post earlier. We've had a bit of a crazy time here, and I wasn't in a very good mood when I posted. I think I read more into his post than was warranted.
That being said, somewhere in my "piles of files" I have an article on dyes, that a finisher gave me years ago, covering wood, leather, bone, stone, etc. If I can find it, I'll post a link, or at least post the part on bone. I do remember bone & stone were what were called "immersion" processes, IIRC.
thx - cpr