The optical reflectivity of Hg 2.91SbF 6 single crystals was measured in the visible and near infrared regions with light polarized parallel and perpendicular to the mercury chains. The results for the parallel polarization were fitted to a dielectric model consisting of a Drude term and two Lorentzian functions describing peaks in the visible. The spectrum for the perpendicular polarization had a reflectance peak in the visible and a small, relatively constant reflectance in the infrared. The results show that Hg 2.91SbF 6 is an anisotropic metallic conductor.