We present our initial work on using a magnetic ring as a tangible input control to support around-device interactions for mobile devices, aiming to address touchscreen issues such as occlusion and imprecision, at the same time provides tangibility to interaction. This input mechanism allows users to use the surface on which the mobile device is placed as an extended input space, with a rotatory motion as the main form of interaction. Our technique requires no calibration, no modifications to the mobile device, and no external power for the ring, which also functions as an accessory item (a finger ring) when not in use. We discuss our design criteria, prototype implementation and illustrative applications, and directions for future work.