Just a rock...Suggestion, look for a couple books on indian artifacts at the book store. that rock would never had been used, it would fall apart too easily..
Looks like granite, which will flake off naturally like that when a boulder or outcrop begins to decompose. See the spot I circled in the pic? You can see where flakes of the decomposing granite has been "flaking" off. That is exactly what your rock looks to be from!
When you post please tell where it was found and state. It looks like a rough material with schist in it. I have found some worked out of that rough stuff before in the past. That stuff is hard to tell if its anything holding in hand let alone on a comp screen.