What's funny is.. I kept thinking I need to find me some decent bone to make more hairpins

Shiny white bone looks good on most brown hair, with wood you have to be quite careful to hit a tone that goes well with the hair it's gonna stick in.
Wood is fine as a material, though. I'm quite sure wooden pins where always way more common than any finds suggest, since wood is gone more quickly. I don't put on any finish but burnish the pin with a piece of glass, that makes a fine surface.