Abstract: Method for marking objects by the use of memory micro-crystals, consisting in choosing one or several micro-crystals, of doping each micro-crystal, if this has not already occurred naturally, with any one of the rare earths and transitional metals, in irradiating the micro-crystal or micro-crystals with high-energy rays or particles, according to a predetermined dosage in order to trap the charge carriers, released by ionization of the atoms, while in their energetically metastable state, said process consisting also in applying a predetermined quantity of the micro-crystal or micro-crystals irradiated by said method, to at least one predetermined part of the object, and in safely recording, for the purpose of later comparison, the characteristics, implantation and conditions under which dopage and irradiation of the micro-crystal or micro-crystals took place. Application to the authentication of objects.