19cm long tooth?

[Wayt Gibbs]

I inherited my grandfather's modest fossil collection, and in it was this 8 cm wide by 19cm long fossil that I need help identifying. It is pointed at one end, has external ridges and an internal hollow at the other--features that look tooth-like to me, but I'm a newbie at this. Unfortunately I have no information on location of discovery or likely age. My hope is that fossils like this are common enough that one of the more educated and experienced here will recognize it right away. I'd be grateful even for best guesses that help me direct further research. 

[Uncle Siphuncle]

Mammoth tooth plate

[Wayt Gibbs]

Thanks so much!

[Shellseeker]

16 hours ago, Wayt Gibbs said:

Thanks so much!

The chewing surface of Mammoth Teeth look like this:  As the animal chews food, the surface is ground down (There has been less grinding on lower right than on upper right.) The tooth consists of enamel plates stuck together by cementum. You have one of these plates.

 

Your plate (below) has the root end on the left and the chewing surface on the right.  It seems that the chewing surface on your plate had not been used or only slightly used.