Nuclear magnetic resonance (NMR) can be a helpful adjunct to x-ray diffraction (XRD) in ascertaining the state of diagenesis of archaeological bone. In the examination of a 15,000-year-old fossil bone from La Riera Cave in Spain, it is shown that XRD indicates the presence of calcite, calcium phosphorus hydrate, and a hydroxy apatite containing 0.5% carbonate, but shows no trace of organic material. NMR spectroscopy has identified the carbonate environments associated with two of the mineral components of the sample (calcite and a component containing carbonate in an apatitic environment) and can detect the small quantities of remaining organic material.