Abstract: A pressure actuated fracture tool for use in splitting and fracturing hardened material, such as rock, stone, concrete and the like, having two expansible outer shells designed to move in opposition to each other along a selected axis transverse to the longitudinal axis of the tool. The outer shells define a central orifice extending longitudinally to length of the tool. An elastomeric tubular member is positioned in the central cavity between two longitudinally fixed end connectors. Upon the application of pressure to the tubular member, the outer shells expand outwardly in a determined radial diversion to contact the wall of a cavity bored in the hardened material and cause the material to cleave or split.