Diamond nanoparticles (nanodiamonds) are a constituent of diverse systems including interstellar dusts and meteorites or carbonaceous residues of detonation. Nanodiamonds have a wide range on applications as engineering materials. New production methodology is now opening new potential applications which include drug delivery and bioimaging. The nature of the surface determines how the particle behaves. Unfortunately, the coat is poorly understood, with models and some experimental evidence giving contradictory results. However, the infrared spectra is dominated by modes assigned to oxygenated functionalities and the Raman spectrum only shows the diamond core. INS spectroscopy is essentially ?blind? to both carbonyls and the core, thus it offers the possibility of new information about the surface hydrogen structure.