USGS Spectral Library. Researchers at the USGS Spectroscopy Laboratory have measured the spectral reflectance of thousands of materials in the lab and compiled them in the USGS Spectral Library. The spectral library was assembled to facilitate laboratory and field spectroscopy and remote sensing for identifying and mapping minerals, vegetation, and manmade materials. For many of the samples, wavelength coverage spans the ultraviolet, visible, near-infrared, mid-infrared, and far-infrared regions (0.2 to 200 microns). A wide range of materials are included in the library: Minerals; Soils (including rocks, and mineral mixtures); Coatings on rock surfaces; Liquids, including mixtures of liquids, water and other volatiles, and frozen volatiles; Organic compounds, including biochemical constituents of plants and chemical compounds; Manmade materials, including materials introduced into the environment by human activity; Vegetation and other biologic materials; Detailed sample descriptions are provided with the spectra, including the results of X-ray Diffraction, Electron Probe Micro-Analysis, and other analytical methods.