Superconductor cables are most commonly used in high magnetic field devices and applications such as Magnetic Resonance Imaging (MRI). Superconductor is an industrial material, it’s not made specifically for jewelry. Due to this, it can have some flaws in it that come out during the etching process. These flaws can vary from small voids in the material to black markings. The industrial nature of superconductor is part of what gives it the rugged appeal that many people enjoy, but it is something to consider when ordering a superconductor wedding ring.