HYDROTHERMAL SYNTHESIS AND MORPHOLOGY OF EULYTITE-LIKE SINGLE CRYSTALS

Visually homogeneous eulytite-type crystals Bi4Si3O12 (BSO) and Bi4Ge3O12 (BGO) have been synthesized by spontaneous nucleation in hydrothermal NH4F, HClO4 and KOH solutions. These crystals have also been obtained on the seeds of Czochralski grown bismuth germanate. Their growth rate increases with increasing concentration of solvent, crystallization temperature and temperature gradient. The synthetic crystals tend to grow with strongly developed {211} and {211} faces. External and internal morphology of these crystals are similar to their natural prototype, and they can serve for identification of the simple forms in this mineral