High-Pressure Synthesis and Characterization of Single-Crystal Diamond–Jadeite Intergrowth

Diamond–jadeite intergrowth was induced at 5.3 GPa and 1310 °C via a temperature-gradient method. NaCl and Al2O3 were used as the seed-bed, Fe–Ni was used as the metallic solvent, and Ni2O3 and P were used as additives. Jadeite, with a distinct green color, nucleated predominantly on the diamond surface. The green phase was identified as NaAlSi2O6 (jadeite) via X-ray diffraction spectroscopy, Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The presence of trace amounts of Cr in the catalyst made the jadeite appear green, and its structure and composition were similar to those of natural jadeite. Furthermore, the experiment also revealed that the presence of jadeite significantly influenced diamond crystal growth, resulting in a large number of layered growth defects on the surface of the diamond crystal. These results demonstrated that diamond and jadeite─both mantle minerals─could crystallize simultaneously under the same pressure and temperature conditions. This finding provides a novel perspective for experimental research in high-pressure geological science.