A formation breaking apparatus with increased wear-resistance is disclosed. In one aspect of the invention, the apparatus has an assembly attached to an end of an articulated arm. The assembly has an actuator in mechanical communication with an axially guided penetrator. The penetrator may have a body intermediate a proximate end and a distal end; the proximate end being adapted to communicate with the actuator, and the distal end comprising a hard material with a hardness of at least 63 HRc.