A method including obtaining an at least partially transparent object (1), providing a mask (6) defining at least one opening (8) wherein the contour corresponds to a profile of the anti-counterfeit marking to be structured, the mask (6) covering a surface of the at least partially transparent object (1) at the areas not to be structured, structuring the anti-counterfeit marking by bombarding the at least partially transparent object (1) by an ion beam (14) through the at least one opening (8) of the mask (6), the mechanical properties of the mask (6) being sufficient to prevent the ions of the ion beam (14) from etching the surface of the at least partially transparent object (1) at the areas where this surface is covered by the mask (6), removing the mask (6), and placing the at least partially transparent object (1) in a bath (16) at alkaline pH.