A portable consumer device having a substrate layer, a protective layer and a diamond-based brittle material layer having an intentionally created unique fissure or cracked patterns or crystal zone boundaries and systems and methods for making and using same are disclosed. The diamond-based brittle material layer includes a diamond material. The unique random fissure or cracked pattern and crystal zone boundaries, or the electromagnetic signature based thereon, of the brittle material layer are detected and used to authenticate the portable consumer device.