The low melting point of Zn and the high melting point of ZnO, as well as their hexagonal crystal structures, present great advantages for designing and fabricating various metal/semiconductor core/shell nanostructures. By controlling the kinetics in the Zn and ZnO system, the lower-energy facets, and the oxidation rates of different surfaces, we can control the fabrication of Zn/ZnO core/shell single-crystal, polycrystalline, and mesoporous nanodisks, as well as a variety of ZnO nanotubes. The oxidation of a Zn nano-object leads to the formation of Zn/ZnO core/shell nanodisks. A lower oxidation temperature results in the formation of a single-crystal-like Zn/ZnO core/shell structure, while a higher oxidation temperature leads to the formation of textured and even polycrystalline nanostructures. A re-sublimation process of Zn in the core leaves a ZnO shell structure. This is an approach for synthesizing metal/semiconductor core/shell or composite nanostructures. This article offers a detailed description of the kinetics controlling the procedures, the nanostructures obtained, their morphological and crystal structures, and their formation mechanisms.