Analysis of Miniature Thermal Emission Spectrometer (Mini-TES) data has led to the recovery of a pure end-member spectral shape related to the light-toned outcrop observed at Meridiani Planum. Data from the MER M¿ssbauer spectrometer, APXS, and previous Mini-TES measurements were used to constrain a spectral library used to determine the mineralogy of the outcrop from this spectral shape. Linear deconvolution of the outcrop spectral shape suggests that it is composed primarily of Al-rich opaline silica, Mg-, Ca-, and Fe-bearing sulfates, plagioclase feldspar, nontronite, and hematite. Conversion of modeled mineralogy to chemistry shows good agreement with the chemical composition of the outcrops determined by APXS. Details of the analysis procedure and implications for the formation of the outcrop are discussed along with terrestrial analogs of the ancient environment at Meridiani.