Mid-infrared spectra of H-OC. The spectra correspond to milled samples, with grain size between 1–10 μm. The data presented are normalized to the maximum in the range of 8–12 μm and vertically shifted for a better appreciation of shape and peaks. The vertical lines correspond to characteristic absorption bands of different minerals: light blue, for the water bands (OH); green for olivine bands, orange for the pyroxene bands, and red for plagioclase (Chihara et al. 2002; Koike et al. 2003b; Beck et al. 2014; Chihara & Koike 2017).