Ratio spectra of ordinary chondrites with different grain sizes, obtained by dividing the spectrum of the smaller grain size fraction by that of the larger grain size fraction, and fit using the weathering function defined by Eq. (5). (a) Thirteen ratio spectra of H chondrites from 10 meteorites; (b) fourteen ratio spectra of L chondrites from 9 meteorites; (c) sixteen ratio spectra of LL chondrites from 15 meteorites. For clearer visualization, the spectra are appropriately scaled and vertically offset. The C_Sa − C_S0927 values derived from Eq. (5) are labeled beside each ratio spectrum. The poor fit indicates that the weathering function is not suitable for describing grain size effects.