I sort of feel like this is not an artifact. I believe it is a concretion that has spent time in moving water. As far as what a concretion looks like, they can look like nearly anything, but here are some examples:
....Hi JoeyZR1.....I respect all of the suggestions given. I kind of like Campfire's bearing block idea...Looks like it would fit in the palm comfortably. If I FOUND IT, I would use it that way !
....Welcome , Both of you from Southern California !