A method for preparing a synthetic material having an organic phase and a mineral phase which consists in preparing an initial acidic aqueous solution of collagen which is a precursor for the organic phase (I), and at least one aqueous solution of precursors for the mineral phase (II), and in precipitating the collagen by increasing the pH to a value of at least 7. The method includes the concentration of collagen in the acidic aqueous solution is at least 75 mg/ml and remains constant during said increase in pH. The mineral phase precursors have at least one calcium salt and at least one phosphate salt. The precipitation of the mineral phase (II) is carried out by bringing the mineral phase precursor solution into contact with the organic phase (I), the bringing into contact being carried out before or after the precipitation of the organic phase (I).