Left: spectra of two ROIs (90 × 90 µm² each) with distance values below the threshold (ROI 1 and ROI 2) in grains A0017 and C0093. The average spectra of grains A0017 and C0093 are also shown for comparison. Spectra of two asteroids measured by the AKARI space telescope are also plotted: 121 Hermione and 2 Pallas (Usui et al. 2019) The spectra measured by MicrOmega have been resampled to the spectral sampling of AKARI data. Right: dispersion graph between the FWHM and the peak position of the 3 µm band for different spectra of Ryugu samples (ROIs with a 3 µm band in purple, average spectra in red, and A0159-exposed in black) and asteroids from the AKARI survey (orange).