Vapor-liquid-solid is a well-established process in catalyst guided growth of 1-D nanostructures, i.e., nanobelts and nanowires. The catalyst particle is generally believed to be in the liquid state during growth, and is the site for impinging molecules. The crystalline structure of the catalyst may not have any influence on the structure of the grown nanostructures. In this work, using An guided growth of ZnO, we show that the interfaces between the catalyst droplet and the nanostructure grow in well-defined mutual crystallographic relationships. The nanostructure defines the crystallographic orientation of the solidifying An droplet. Possible alloy, intermetallic, or eutectic phase formation during catalysis are elucidated with the help of a proposed ternary Au-Zn-O phase diagram.