Figure 1. Ground-based telescopic spectra of Mercury at a range of wavelengths. A: Ultraviolet–visible wavelength reflectance spectra (McCord & Adams, 1972a). The two spectra (scaled to 1.0 at 0.55 μm and offset for clarity) are red-sloped and relatively featureless. B: Mid-infrared emissivity spectrum (Sprague et al., 2009). A peak associated with the presence of pyroxene (e.g., diopside or augite), at ~5 μm, is labeled.