Formation of the high pressure jeffbenite phase from glass at ambient pressure

Jeffbenite is a magnesium aluminosilicate phase (nominally Mg₃Al₂Si₃O₁₂) found naturally in close association with diamonds. It has been synthesized at pressures as low as 6.5 GPa. We report here the synthesis of crystalline jeffbenite solid solutions at ambient pressure, through the controlled crystallization of glass. The resulting glass-ceramic materials can have between 20 and over 60 wt% crystalline jeffbenite. X-ray diffraction, ²⁷Al NMR, Raman spectral analysis, density, and elastic property evaluation all support the identification of this phase precipitating from glass. A mechanism for the nucleation and formation of this high-pressure phase, at ambient pressure conditions, is presented. Glass-ceramics based on jeffbenite may be transparent or opaque, have high modulus and hardness, and can be strengthened by ion exchange for a possible range of technical uses.