Native American hammer stone?

I dug this up in my back yard in northern NJ when digging an 18” deep trench for an electric line. It’s grooved on 3 sides, and it seems hard to imagine someone living in my house making this and burying it.

There is a small river nearby that it could have come from. Anyone have any thoughts on authenticity or age? My daughter is studying Indigenous history and we’d be super excited if it were real (and if it’s of any value I’d be happy to donate it to a museum).

Thanks