Abstract: We suggest a new laboratory method for synthesizing coesite in the earth's crust by considering the similarity characteristics of local collisions and shearing strength between the earth's plates and high energy mechanical ball milling(MBM), combining the high-energy MBM and high static pressure and high temperature technique, and using mixtures of α-quartz and graphite as the initial material. The nanometer amorphous mixture of α-quartz and graphite was prepared by high-energy MBM. The lowest pressure and temperature for synthesizing coesite are 3.7 GPa, 970 K. The Raman spectrum of synthetic coesite possessed ten peaks located at 120, 152, 179, 206, 270, 329, 357, 428, 467 and 521 cm^-1. The obtained spectrum is coesite Raman spectrum with the most peaks among published results. The author attempts to look for useful information about the mineral circumstance of coesite in the Earth'surface and the mechanism of the ultrahigh-pressure metamorphism.

Key words: α-Quartz-graphite, Coesite, High-energy mechanical ball milling, High temperature and high pressure