I've made bone nuts by hand for a quite a while now, and I've been experimenting with buffalo horn as an alternative since shiny white parts look a little out of place on some guitars. It takes a little faith because it looks terrible and in no way suitable in its raw state, but it cleans up well and takes a polish. Turning from grey to to a deep black that resembles polished ebony. Example below on a tele copy that needed a new nut this week, I'm liking it.