My antlers are about 10 inches long and about 1 to 1.5 inches in diameter. I think they are from deer, not elk, but it is hard to tell. They say they get them from naturally shed antlers and from venison processing plants. I believe that as two of my three antlers look sunbleached, the third one looks like if just came off the deer. My dogs actually like the ones that look sunbleached the best.
Ringo is a power chewere and it takes him a long time to even make a dent in the antlers, and so far none of them have split. They only look ground down.
Murfsma - Yep, the antler dropped on the tile floor is pretty noisy. The other thing Ringo likes to do is grab one end of the antler in his mouth leaving the rest of it sticking out and run through the house hitting walls, etc. I try to keep him from doing that as I don't want my walls and furniture gored. That, however, is much better than having the furniture chewed which was the case before we got the antlers.