Close-up of selected characteristic spectra of the Ryugu samples in the 1900−100 cm⁻¹ range, with pure mineral spectra shown for reference (dolomite and magnesite, Roush 2021; breunnerite Mg_0.78Fe_0.22CO₃, this work; FeS Henning & Mutschke 1997; magnetite, Glotch & Rossman 2009; saponite and serpentine, Glotch et al. 2007). In the upper part of the figure, vertical dashed dark-green lines have been added to highlight the positions of specific small features of serpentine. In the lower part of the figure, vertical dashed blue lines are guides to the eye to show the characteristic positions of IR features in dolomite, which is the main carbonate identified in this work (see text for details).