Abstract
An internal heating hydrothermal apparatus which can be used up to 1000°C and 300MPa, was designed to realize high temperature hydrothermal conditions. Transparent beryl crystals were grown in 0.025-0.05N NaOH solutions on the seed above 600°C and 160MPa. Step and pyramidal growth patterns were observed on the surfaces of the crystals grown on the seed crystals with a (1120) and s (1121) faces. Relatively high growth rate (30-40μm/day) was attained for the both seed crystals. Water molecules and alkali cations were incorporated into the channels of the beryl structure as in natural emeralds.
