It may be the form fitting earth which hardened into rock around a concretion. To verify 100% would be impossible from a photo. One would have to take into account the other material found in association with the rock to have some sort of a percentage guess if it is, or is not an Indian made artifact.
You do not mention if any other relics or debitage is found in the area where this was found, and if any were in the area, how close and it what association.