Translucent, high-performance, mullite ceramics with anisotropic grains were prepared by the spark plasma sintering (SPS) of a powder mixture consisting of commercial mullite powder, which already contained small amounts of alumina (theta and alpha) and silica (cristobalite) (<= 3 wt% in total), to which 2 and 1 wt % of yttria and amorphous silica was admixed, respectively. The combination of low-viscosity Y2O3-Al2O3-SiO2 transient liquid formation and SPS sintering provided enhanced densification, also provoking anisotropic grain growth (which became exaggerated after 20 min of SPS dwell time), at a relatively low sintering temperature of 1370 degrees C. In this way, it was possible to meet the conflicting demands for obtaining a dense mullite ceramic with anisotropic grains, ensuring good mechanical properties, while preserving a noticeable light transmittance. In terms of mechanical and optical properties, the best results were obtained when SPS dwell times of 5 and 10 min were employed. The as-sintered samples possessed densities in the range 3.16-3.18 g/cm(3), anisotropic grains with an aspect ratio (AR) of 7 and a grain thickness of approximately 0.45 mu m, a flexural strength between 350 and 420 MPa, a Vickers indentation toughness and a hardness of approximately 2.45 MPa.m(1/2) and 15 GPa, respectively, and an optical transmittance of between 30% and almost 50% in the IR range.