Abstract: An Apparatus and method for breaking off cores from a material to be tested includes a tube split by opposing slots, a tightening device for moving confronting ends of a split tube towards each other so that the split tube grasps the core to be broken, and a handle for exerting lateral forces to break off the core. The core breaker is inserted into a space left by a core drill bit. The split tube is tightened around the core to be broken off, and lateral pressure is then applied to the handle to break off the core.