One of our detecting forum members found an original frontier one with an ivory (whale?) handle in an old tool box he bought for a buck or 2 at a damn yard sale. THAT was killer luck.
A coworker is really into knives, (altering/making) and he also had a 3 or 4 foot slab of wooly mammoth tusk from his father. He also came across an ~50 year old Bowie blank never completed by his father. I pestered him for a couple years that he should make that Bowie with an ivory handle, he finally did, it was awesome, and later he sold it to me for $400 and I gave it to Pops :-)