Abstract:A new coexisting amphibole pair was recently found in Jianshan iron deposit Leufan of Shanxi Province, China. Electron microprobe analysis shows that the coexisting pair is composed of grunerite K0.001(Na0.027Ca0.073Mn0.031Fe1.8012+ )1.932 (Fe2.9482+Mg1.964Ti0.002 A10.087)5Si8.069O22.10 (OH)2 and ferropargasite (K0.135Na0.0461)0.596 (Na0.088Ca1.853Mn0.005Fe0.0722+)2 (Mn0.005Fe2+2.789Mg0.875Ti0.021 Fe0.4993+Al0.812)5(Si6.103Al1.897)8O22.00(OH)2. The two kinds of amphiboles occur in amphibole schist not only as separate phenocrysts but also combine to form " single- crystal" phenocrysts in the form of topotactic integrowths with the common c- and b-axes. The boundary between the topotactic grunerite and ferropargasite is optically and chemically sharp. In comparison with the coexisting magsioferruginous amphibole and calcareous amphibole pair discovered by predecessors, the newly discovered pair has lower Mg/Fe ratios and wider miscilibility gaps.