Presence of water tends to weaken some minerals, particularly quartz. If water is present, the amount of axial load and also the confined pressure required to rupture quartz gets much reduced. Thus, the experimental studies in this direction which were initiated by Griggs and his coworkers had showed that quartz cannot plastically deform even at high temperatures of 800 C and high confining pressure of 500 MPA. Carter and his coworkers could plastically deform quartz only at 1000 C and confining pressure of 2000 MPA. Even under such experimental conditions, it was found that quartz did not show any appreciable dislocations and most of the deformation was by development of shear fractures. But it is found that quartz deforms very easily and appreciably under natural conditions. If the water is made available during the experiment to quartz, then quartz can deform plastically under very low temperatures such as 800-1000 C and confining pressures of 1500 MPA or even less.