Wooly Mammoth tusk
From late 1996 to mid-1999, I was part of the inspection team at the construction of three earthen dams at Diamond Valley Lake near where I live. During the process of excavating the rich clay deposits in the valley for use in the dams, many paleontological discoveries were made and because the project was so large, there were teams of paleontologists working almost around the clock recovering them. The valley became known as the Valley of the Mastodons although many other creatures were unearthed there.
This is a small fragment of a tusk from a Wooly Mammoth that was uncovered there and given to me by one of the paleontologists. It's about 1 3/4" long and 1 1/4" wide.