Laboratory reflectance spectra (Mineral and Rock Sample Database, Planetary Spectrophotometer Lab, University of Winnipeg; E. Cloutis et al. 2006) of candidate minerals in Mercurian regolith compared to graphite (averaged spectrum of GRP103 through GRP107; see Figure 6) and the Mercury median reflectance between 30°S and 30°N as measured by MDIS. Dashed lines are FeO-bearing varieties exhibiting strong absorptions near 1 μm (1000 nm) that are not evident in spectra or reflectance ratios of Mercury.