Pulsation processes at hydrothermal crystal growth (beryl as example)

The experiments on beryl hydrothermal growth showed that spontaneously form ed growth zonality in crystals can be explained by sporadic temperature flu ctuations at similar to 0.7 degrees C amplitude. Model experiments under no rmal conditions proved that such temperature fluctuations in the growth med ium can be generated in hydrothermal growth processes. They are due to the pulsation character of heat-mass transfer in autoclave. The model is sugges ted to explain the hydrothermal crystal growth as a result of the instant l ocal overcooling of the diffusion layer when they are in contact with the c old portions of hydrothermal solution. (C) 1999 Elsevier Science B.V. All r ights reserved.