Effects of mineral content on the fracture properties of equine cortical bone in double-notched beams

► Fracture initiation toughness was measured using a double-notched beam in four-point bending and mineral quantified using backscattered electron imaging. ► Mineralization around the two notch roots was positively correlated with fracture toughness (r2 = 0.34) and negatively with crack extension (r2 = 0.81). ► Energy absorbed was negatively correlated with average mineralization of the beam (r2 = 0.62), but not with notch root mineralization. ► High notch root mineralization decreases stable crack growth and increases the force to initiate unstable crack growth. ► High average mineralization reduces energy absorption to failure.