Described herein is a method that comprises: —placing a bone material, containing hydroxyapatite and organic substances, in contact with an extraction liquid that gives rise to a first liquid phase, containing the organic substances and possibly impurities extracted from the bone material, and a second solid hydroxyapatite phase, containing the hydroxyapatite; and —separating the liquid phase and the solid hydroxyapatite phase. The extraction liquid is an aqueous extraction solution brought to a temperature between 150° C. and 300° C. and a pressure between 150 kPa and 350 kPa.