Students use DRIFT spectra and multivariate analysis to characterize sands collected from different locations. A principal component analysis shows that the scores for the first and fourth principal component allows students to identify samples collected from different areas. The scores plot distinguishes between samples that are carbonate-rich and that are silicate-rich. For carbonate-rich samples, it is possible to distinguish between those that are dolomite-rich and those that are not; for the silicate-rich samples there is some separation between those samples rich in quartz and those rich in feldspar.
The full citation is here: De Lorenzi Pezzolo, A. J. Chem. Educ. 2011, 88, 1304–1308 and a link to the article is provided below (subscription to the journal required).