An unusually anisotropic growth or quasi-one-dimension growth of silver architectures can be achieved when an external magnetic field is applied to a simple replacement reaction. The external magnetic field greatly promotes the growth of trunks along < 111 > directions but weakens the growth of branches along < 311 > directions, resulting in a silver icker-like architectures. The influences of the external magnetic field, solution concentration and reaction time have been investigated in detail. The formation of silver icker-like architectures could be attributed to shape magnetic anisotropy and fast complex micro-magnetohydrodynamic (MHD) convection effects induced by the external magnetic field of the nanoparticles possessing a truncated octahedron structure. Moreover, the magnetic field effect on the crystal growth of nanostructures generally involves the ion-mediated growth process or the aggregations of numerous nanoparticles along the magnetic field directions because of dipolar interactions. Our experiments and discussions, however, indicate that metal crystals are grown through a multistep particle-mediated growth process with the nanoparticles as basic building blocks. (C) 2013 Elsevier B.V. All rights reserved.