We studied the experimental Raman spectra of various commercial silica nanoparticles of average diameter from 7 to 40 nm and specific surface from 50 to 380 m2/g. We found that the peculiarities of the particles Raman spectra systematically depend on their specific surface. In detail, the peak position of the R band at about 440 cm−1 shifts towards high wavenumbers following an almost linear dependence on the specific surface. Similarly, the amplitudes of the D1 and D2 bands, at about 495 and 605 cm−1, respectively, increase linearly with the same quantity. Our results are interpreted in the frame of the shell model for the nanoparticles clarifying that the network of the core of the nanoparticles is comparable to the bulk silica materials, whereas the surface shell has a ring statistic shifted to the low member rings and features an higher density. Copyright © 2013 John Wiley & Sons, Ltd. Our Raman investigation on silica nanoparticles with specific surface from 380 to 50 m2g‐1 (diameters from 40 to 7 nm) sheds new light on the shell model. The Raman spectrum of the core is essentially the one recorded in nanoparticles with lower specific surface, whereas the spectrum of the surface shell is essentially the one of the nanoparticles with the higher specific surface. These results evidence the differences in the structure and density of these two nanoparticle regions.