Method for measuring the tenacity K c of a material, comprising the following steps: - placing a test piece of said material in the form of a cuboid drilled at its centre by a central hole between two jaws of a compression testing device, each of said jaws pressing on a far end (4,6) of the test piece; - bringing the two jaws towards each other to apply a force to each of said ends (4,6) until the test piece fails completely; - measuring the variations of the compression force applied at each end (4,6) of the test piece as a function of the time, during compression; - determining the maximum value F 0 of said compression force; - marking three distinct zones on one of the failure surfaces, namely a first zone close to the hole with a first type of relief corresponding to a fast propagation rate of the crack, a second zone with a second type of relief corresponding to a stable propagation rate of said crack, and a third zone with a third type of relief less pronounced than the second type corresponding to sudden acceleration of the crack propagation until crack failure occurs, method characterised by the following steps: - measuring the distance L 0 between the edge of the hole and a transition line separating the second zone from the third zone, said transition line materialising the beginning of the sudden acceleration of the crack propagation until test piece failure occurs, - calculating the parameter K c as a function of the force F 0 and the distance L 0. - placing a test piece of said material in the form of a cuboid drilled at its centre by a central hole between two jaws of a compression testing device, each of said jaws pressing on a far end (4,6) of the test piece; - bringing the two jaws towards each other to apply a force to each of said ends (4,6) until the test piece fails completely; - measuring the variations of the compression force applied at each end (4,6) of the test piece as a function of the time, during compression; - determining the maximum value F 0 of said compression force; - marking three distinct zones on one of the failure surfaces, namely a first zone close to the hole with a first type of relief corresponding to a fast propagation rate of the crack, a second zone with a second type of relief corresponding to a stable propagation rate of said crack, and a third zone with a third type of relief less pronounced than the second type corresponding to sudden acceleration of the crack propagation until crack failure occurs, method characterised by the following steps: - measuring the distance L 0 between the edge of the hole and a transition line separating the second zone from the third zone, said transition line materialising the beginning of the sudden acceleration of the crack propagation until test piece failure occurs, - calculating the parameter K c as a function of the force F 0 and the distance L 0. - measuring the distance L 0 between the edge of the hole and a transition line separating the second zone from the third zone, said transition line materialising the beginning of the sudden acceleration of the crack propagation until test piece failure occurs, - calculating the parameter K c as a function of the force F 0 and the distance L 0.