  We provide precise fitting formulae for Faraday conversion and rotation
coefficients in uniformly magnetized relativistic plasma. The formulae are
immediately applicable to Rotation Measure and Circular Polarization (CP)
production in jets and hot accretion flows. We show the recipe and results for
arbitrary isotropic particle distributions, in particular thermal and
power-law. The exact Faraday conversion coefficient is found to approach zero
with the increasing particle energy. The non-linear corrections of Faraday
conversion and rotation coefficients are found essential for reliable CP inter-
pretation of Sgr A*.
