Reflectance spectral libraries are essential reference databases for the mineralogical characterization of geological samples analyzed using visible and infrared spectroscopy. Since 2011, the Geological Survey of Brazil has been actively developing a comprehensive database of reflectance spectral signatures, based on samples collected from systematic geological mapping and mineral resource projects across the Brazilian territory. This spectral library is now available on a digital platform hosted by the Geological Survey of Brazil's geoscientific database, providing quantitative data for the numerical characterization of lithological types and their alteration products, whether due to weathering or hydrothermal processes.