The Hetian nephrite deposit located south of the Tarim Basin in Xinjiang is a typical superlarge dolomite-related nephrite deposit. In this ore deposit, the Alamas ore belt explored about two hundred years ago is an important ore belt, and, since 1975, it has produced more than 100 tons of wonderful white nephrite. In this ore belt, different nephrite zoning structures exist as veins or lenses vertically or horizontally within the contact zone between dolomite marble and granodiorite. Nephrite zonings also stay with a variety of other mineral assemblages such as zeilanite, diposide and tremolite, boltonite dolomite marble, and serpentinized dolomite marble. Sometimes, there exists bicolor nephrite or nephrite and tremolitized nephrite zoning, i.e., one specimen representing a zoning transition can be easily found in this location. However, among nephrite deposits, obvious nephrite zonings are very uncommon, and there are few reports documenting them. Therefore, to explain the causes and genesis of such nephrite zoning structure, the authors carried out chemical analysis of samples collected from these nephrite zonings by means of electronic microscope probe analysis (EMPA) and ICP-Ms. All the amphiboles in the nephrites have very low content of Cr (Cr=8.95×10^-6～178.7×10^-6) and Ni (NiO=0.05×10^-6～3.95×10^-6) relative to serpentinite-related nephrite (Cr₂O₃=0.07%～0.43%; NiO=0.08% ～0.36%). The results indicate that such color-causing elements in nephrite as Fe, which mainly occur in tremolite, exhibit decreasing concentration as color changes from green to white, a trend which is consistent with the zoning structures. Based on these observations, the authors have further concluded that the variations from high to low temperatures are consistent with the distribution of zonings, as clearly demonstrated by the tremolite grain size. Therefore, these geochemical characteristics and mineral assemblages in the contact zone are strongly indicative of a dolomite-related ore deposit with metasomatic origin for the Alamas nephrites.