Spectral reflectance properties of carbonaceous chondrites: 1. CI chondrites

► Most CI reflectance spectra exhibit mineral-associated absorption bands. ► Magnetite seems the likeliest explanation for blue-sloped CI spectra. ► Larger grain size samples generally have the bluest and darkest spectra. ► Phase angle can cause CI spectra to become redder or bluer. ► Underdense CI samples have lower reflectance than regularly packed CI samples.