The Raman spectra of a number of orthosilicates of the garnet, zircon, olivine, phenacite, and other groups have been measured and modes due to the internal vibrations of (SiO4) groups assigned; a number of isostructural compounds were also studied. Spectra were also measured of minerals containing (Si3O9), (Si4O12), and (Si6O18) rings (benitoite, catapleite, axinite, dioptase, beryl, and tourmaline) and group assignments for these and other cyclosilicates suggested, the spectra of model ring compounds of germanates and phosphates being used as a basis.