The electrical and dielectric response of muscovite ruby mica has been investigated by measuring various parameters (Impedance, Impedance phase angle, Susceptance, Admittance, Dissipation factor or tanδ, Quality factor, Static capacitance in series-equivalent circuit mode, Static capacitance in parallel-equivalent circuit mode) as a function of frequency (range between ~10 MHz to 120 MHz) at different annealing temperature (range between room temperature to 1050 o C). The present work reveals the influence of thermal treatment on the electrical/dielectric characteristics of muscovite ruby mica. The high temperature annealed mica shows approximately 72% low quality factor as compared to the unannealed mica. This paper will be helpful for the better utilization of muscovite in various high temperature and frequency equipments.