One unshocked and 9 naturally shocked single quartz crystal grains with 1-6 sets of shock lamellaefrom the Ries, West Germany, and the Lake Lappajarvi, Finland, covering a range from unshocked quartzwith No=1.544 to nearly completely glassy quartz with No=1.461 have been used for X-ray precessionand Laue investigations. Four of the shocked grains have preliminarily been studied under a transmissionelectron microscope. It is found that quartz having No less than 1.539 shows intensive anisotropic cellexpansion and lattice disordering which gradually increase as No decreases. Shock-induced lattice distortionof quartz is clearly shown on both precession and Laue photographs. For the weakly shocked quartz (p<200kb) slight to pronounced spreading of spots is observed. When the pressure reaches 200 kb, both concentricspreading of spots having long ‘tails’ and concentric rings (powder pattern) are revealed on the samephotograph, which means that besides a part of single crystal there also exist randomly oriented tiny‘fragments’ of quartz in this shocked quartz grain. As pressure increases from 230 to 315 kb, more and morecrystalline puases in the quartz grains have transformed from solid state into silica glass, and the concentricrings and the long ‘tails’ disappear and the spot spreading becomes slight again, but reflection intensitiesbecome much lower in comparison with those of weakly shocked quartz. TEM investigations show three kinds of substructures of shock lamellae. The glass contents of two ofthe four grains (73% and 84% respectively) were measured on TEM photographs with the help of an imageanalysis system. On the basis of above investigations a six-terminal-state model for the mechanism of deformation inshock metamorphosed quartz is presented. One unshocked and 9 naturally shocked single quartz crystal grains with 1-6 sets of shock lamellaefrom the Ries, West Germany, and the Lake Lappajarvi, Finland, covering a range from unsocked quartz with No = 1.544 to nearly completely glassy quartz with No = 1.461 have been used for X-ray precession and Laue investigations. Four of the shocked grains have preliminarily been studied under a transmission electron microscope. It is found that quartz having No less than 1.539 shows that the anisotropic cellexpansion and lattice disordering induced lattice distortion of quartz is clearly shown on both precession and Laue photographs. For the weakly shocked quartz (p <200kb) slight to pronounced spreading of spots is observed. When the pressure reaches 200 kb, both concentricspreading of spots having long ’tails’ and concentric rings (powder pattern) are revealed on the same photograph, which means that besides a part of single crystal there also ex ist randomly oriented tiny’fragments’ of quartz in this shocked quartz grain. As pressure increases from 230 to 315 kb, more and morecrystalline puases in the quartz grains have transformed from solid state into silica glass, and the concentricrings and the long ’tails’ disappear and the spot spreading will slight again, but reflection intensities become much lower in comparison with those of weakly shocked quartz. TEM investigations show three kinds of substructures of shock lamellae. The glass contents of two of the four grains (73% and 84% respectively) were measured on TEM photographs with the help of an image analysis system. On the basis of above investigations a six-terminal-state model for the mechanism of deformation inshock metamorphosed quartz is presented.