Described are thin plane-parallel aluminum flakes illustrated in FIG. 1 having a thickness of up to 200 nm and comprising an inner layer of oxidized aluminium having a thickness of 0.5-30 nm, a process for the manufacture thereof and the use thereof, e.g. in formulations, like paints, electrostatic coatings, printing inks, plastics materials, and cosmetics. Surprisingly, due to the inner layer of oxidized aluminum the aluminum flakes have an improved shear stability as evidenced e.g. by the difference in lightness before and after shear stress.