Abstract:Based on field work in fourteen typical ore districts of China, the author made experiments on contact metasomatism of ultrabasic-acid intrusive rocks with carbonate rocks, interaction between volcanic pneumatolyto-hydrothermal solution and volcanic rocks, and metasomatism in the process of sedimentary metamorphism and migmatizatiun. The results show that hibschite, hydrogrossular, grossular, amlradite and their transitional minerals hibschite-hydrogrossular, hydrugrossular-grossular and grossular-andradite might be formed in aqueous solution with K, Na halides of different concentrations and pH 4.0-11.0 under the conditions of 350-700℃, 300×105-1400 ×lO5 Pa and log fO2-- -28 .637- -16.514. The main optical properties of these minerals were determined by such methods as microscopy, X-ray diffraction analysis and infrared absorption spcctromctry.Finally, their formation mechanism was revealed through an analysis of p hysicochemical conditions.