Abstract：An unusual mantle mineral group consisting of more than 100 species (or subspecies) minerals was discovered in chromite from the Yarlung Zangbo ophiolite belt, Tibet. It includes native element minerals, alloys, oxides (arsenides) and silicates. According to experimental data, some of the minerals are ultrahigh-pressure minerals, possibly formed at the Earth's core-mantle boundary, and are the products of chemical reactions between liquid iron of the Earth's outer core and silicates at the base of the lower mantle； others might be derived from the lower mantle, transitional zone and upper mantle. The mantle mineral group in Tibet has great significance in mineralogy and geodynamics.