Abstract. Fe 3+ bearing minerals and poorly crystalline mineraloids can host pernicious trace metals released by mining activities. Such mineral phases are readily detectable in imaging spectrometer data such as is collected by NASA`s Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). Laboratory measured reflectance spectra of fluvial sediment samples gathered downstream from the Summitville mining district in southwest Colorado, U.S.A., have been compared with AVIRIS data collected over Summitville and the surrounding San Juan mountains. Spectra from the AVIRIS image cubes over Summitville match with the laboratory measured reflectance of several Fe 3+ bearing mineral phases including a ferrihydrite produced in an acid water environment.