α-Quartz is one of the most common piezoelectric materials used in piezoelectric devices. It is possible to improve piezoelectric parameters of quartz by incorporating other atoms into an α-quartz structure. In particular, isomorphous substitution of Ge for Si in the α-quartz structure results in a decrease of dynamic disorder at high temperatures and structural distortion which in turn leads to an improvement of thermal stability and better piezoelectric properties [1-6]. Preliminary studies indicate that germanium-containing quartz is a prospective industrial material. The temperature of the α-β phase transition in quartz containing 5-30 wt. % GeO2 is 780-940 °C, i.e. ~ 200-350 °C higher than that for pure quartz. The resonance frequency remains stable up to at least 450 °C, whereas in pure quartz it is stable only up to 280-290 °C [5].  One of the most important parameters of piezoelectric resonators is a quality factor (Q-factor) which depends primarily on their design features and much less on internal friction of the piezoelectric element. However, an improvement in the design of resonators has made it necessary to take into account the parameters of piezoelectric material, which depend on the presence of grain boundaries, dislocations, impurity atoms, and also on the phonon spectrum of the crystal.  In this work α-quartz-type Si1-xGexO2 single crystals (x<0.19) grown under hydrothermal conditions in NH4F solutions were investigated by IR and Raman spectroscopy. Compositional dependences of infrared absorption spectra were found both for fundamental vibrations and overtone and combination vibrations. At low GeO2 concentrations, only the broadening of absorption bands is noticeable, the intensity of new bands is too small. With the increase of Ge content in the crystals new absorption bands corresponding to vibrations O-Ge-O in GeO4 tetrahedra appear, the intensities of absorption bands O-Si-O in SiO2 tetrahedra decrease. The shift of some absorption bands to lower wavenumbers linearly depends on Ge content and is characteristic to the vibrations in Si-O-Ge chains. The origin of some combinational vibrations is clarified.  The shift of the absorption bands in IR and Raman spectra, as well as the broadening of IR absorption bands with the increase of Ge content indicates that Ge enters isomorphously in a position of Si into the quartz structure. There is a continuous series of solid solution in a SiO2-GeO2 system, at least until the Ge content reaches 19 wt. %.  Acknowledgments: The authors thank M.F. Vigasina for her help in interpreting IR and Raman spectra, as well as in collecting Raman spectral data, N. Boldyrev for collecting some of IR spectra and for providing a polarizer, A.I. Efimova for her help with performing polarization measurements, N.N. Koshlyakova and D.A. Khanin for performing electron probe analyzes.