Abstract:Using natural olivine pyroxenite and crystalline limestone or biotite-quartz schist and dolomitic marble as starting materials, the authors performed metasomatic experimentation in 0.5M KCl+0.5M NaF solution with pH 6.0-8.0 at 450-700℃ and under (500-1400) × lO5Pa; as a result, humite group minerals were formed. Humite group minerals formed by metasomatism are colorless (some with light yellotv tone) and transparent. Crystal morphology is perfectly developed with crystal sizes being generally 0.005-0.02mm; biaxial positive. Their optical properties such as refractive indices and their X-ray diffraction patterns indicate that they are chondrodite, humite and clinohumite. The principal conditions for the formation of humite group materials are that the mole number ratio between Mg and Si must be higher than 3:1 in the starting materials which, in addition, should contain saturated H20. Under suitable temperature and pressure, neutral-weakly alkaline solution of K, Na halogenides and oxidation environment are favorable for their growth and development With topologic graphical method. the authors have reached the conclusion that,at constant chemical potential of SiO2. the formation of clinohumite (one of the humite group minerals) and its major paragenetic minera-s-forsterite, brucite and antigorite is dependent on fairly high μMgO and μHO.It is also proved that the coexistence of these minerals is an inherent law in their interaction.