Abstract: A metallic identifying tag for allowing later identification of a non-metallic object. The identifying tag is of a circular or oblong cross-section and has a plurality of spaced grooves cut along the surface thereof. In addition, holes may be provided through the center of the tag in conformance with a predetermined pattern which thus forms a profile readily identifiable by means of x-ray equipment. In this manner, while the tag remains implanted within the object it may be inspected and the coded pattern interpreted and the history of the object containing the tag thus ascertained.