[en] Characteristic lattice distortions and optical inhomogeneity in synthetic quartz were observed by X-ray topography and optical birefringence measurement. Lattice distortions were recognized in connection with the impurity distribution, such as hydrogen bonded OH and substitutional Al, detected by infrared absorption and coloration of γ-irradiation. The contents of such impurities are different in various growth regions. The impurity distribution shows the characteristic pattern. The birefringence variations are interpreted as the influence of hydrogen bonded OH. In the fast-grown quartz, the correspondence between birefringence variations and the OH distribution is clearly observed at the positions of striations. In the Z region of the slow-grown quartz, no birefringence variation is found and high optical quality was observed. The infrared absorption technique is useful for the evaluation of the optical quality. (auth.)