Rock

A Rock is a naturally occurring aggregate of minerals and/or mineraloids. In Fallout and Fallout 2, rocks can be picked up and thrown or used to strengthen a player's Unarmed attacks.

In-game description
It's a rock. The Granite-Inc. model is an upgraded version. Min ST: 1.

Location
The locations rocks can potentially be found in both Fallout games are too numerous to list; suffice to say that if you ever find yourself looking for rocks, you probably don't need to go far.