Spectrum Vis-NIR reflectance spectrum of Huy pigment (PIG_0172_A_608), powder with grains < 50 µm Spectrum Vis-NIR reflectance spectrum of Huy pigment (PIG_0172_A_601), powder with grains < 160 µm, d=1.01 g/cm3 Spectrum Vis-NIR reflectance spectrum of Huy pigment (PIG_0172_A_607), powder with grains 100-200 µm Spectrum Vis-NIR reflectance spectrum of Huy pigment (PIG_0172_A_606), powder with grains 200-400 µm Spectrum Vis-NIR reflectance spectrum of Huy pigment (PIG_0172_A_605), powder with grains > 400 µm