Hydrothermal synthesis and morphology of Ga-bearing tourmaline

Ga-bearing tourmaline was originally synthesized in boron, boron–alkaline, and boron–fluorine hydrothermal solutions at a temperature of 600–650°C and pressure of 100 MPa as crystals of spontaneous growth and on seeds. The maximal concentration of Ga 2 O 3 in synthetic crystals reaches ~24.5 wt %. In addition to Ga-bearing tourmaline, Ga-bearing topaz crystallizes in boron–fluorine solution. Ga-bearing albite crystallizes in boron–alkaline solutions, whereas no additional phases are formed in pure boron solutions.