SILICA AND ALUMINA TRANSFER IN SUPERCRITICAL AQUEOUS FLUIDS AND GROWING OF TOPAZ MONOCRYSTALS IN THEM

Abstract

Silica and alumina transfer during the dissolution and growth of quartz, corundum, and topaz in supercritical aqueous fluids have been experimentally studied under a direct temperature gradient, and the possibility for growing of topaz monocrystals in them have been determined. It was demonstrated that the directions of silica and alumina transfer shows no unambiguous correlation with the composition, PT conditions, pH, and density of the fluids, and, in some cases, can be opposite. This defines simultaneous spatially associated or separated growth of quartz and topaz, as is often observed in camera pegmatites. Our experimental data made it possible to develop a reproducible seed growth of topaz monocrystals and to study their structure, morphology, and physical properties. © Pleiades Publishing, Inc. 2006.