Chamber C Ryugu sample C0040-FC025 (bottom diamond window). Phase maps of silicates (a, green), carbonates (b, red), opaques (c, yellow-orange), OH stretch (d, blue), CH stretch (e, magenta), and corresponding visible images (f). Bottom: images representing the edge detection of individual ROIs based on the intensity map of carbonates (left), and of opaques (middle), and resulting size distribution histograms (right). The x-axis represents the projected surface of each region in μm² (multiples of the spatial resolution of 9 μm²). As the samples are flattened to ~1 μm, this projected surface is directly proportional to the same volume value.