The Helong rockbody occurs in the Jiapigou - Jinchengdong granitic greenstone belt in the late Archaean, which were deformed and metamorphosed simultaneously with the wall rocks, charactered by typical chilled ko-matiite textural stratification, spinifex texture and chilled polyhedric joint. The characteristics as mentioned above are discovered and determined by the authors in 1990. The komatiite has the following mineralogical characteristics: the devitrification of rock forms such minerals as cathkinite; orthopyroxene and olivine spinifex shows intermediate hollow skeletal crystal, most of which are replaced by talc, ankerite, chlorite and magnetite , but still keeps undamaged columnar pseudomorphism; olivine in the accumulation zone shows fine, fresh and net -like serpentinization. Its petrochemical characteristics show that it is rich in MgO and CaO/Al2O3 = 1. 04. It is classified as ultramafic komatiite based on the komatiite classification map.