I use bone for my folders, I get cattle shin bone from the locl butcher, cut the ends off, dig out the marrow and boil it for about 20 minutes, dry it overnight then cut it to size. Bone being most round need a lot of sawing and grinding to get it to a flat piece for a handle. I usually can only get one handle slab per bone.
To get an interesting marble effect, you can boil the bone with the marrow still in, the fat soaks into the bone and makes it look like marbling but it does interfer with gluing the bone.
Bone takes a very good finish. I sand it to 320 grit than use fine steel wool and finish with a fine abrasive like T Cut or Brasso to get a glossy finish.
It looks a lot like ivory.
Heres a pic of a knife with bones scales I made.