Possibly a indian artifact?

[Unitedstatesofamerica1]

There some kind of groove at the end

 

[The Grim Reaper]

Knowing what state and where found would help. Was it from a field or a creek?

 

[Unitedstatesofamerica1]

Pennsylvania and from a field

 

[jamey]

looks like a nice little head knocker

 

[mn9000]

I believe the white lines are quartz veins, I have one very similar that I'll post later today

 

[joshuaream]

Tough piece to call without looking at it in hand. It's not heavily modified, but it's got what looks like pecking in a couple of areas.

If there are a lot of cobbles in the field, then it's probably just a cool rock. If it's not normal for the area, and you've found other relics there then it might be a quick hammerstone or even a cobble that someone collected with the intention of working the raw material into a celt or tool.