Mineral surfaces, particularly Fe-(hydr)oxides, play a predominant role in controlling the composition of natural waters and regulating transport and bioavailability of aqueous contaminants.  X-ray crystal truncation rod (CTR) diffraction is used to investigate surface structures, relaxations, and chemical identity of terminating surface moieties of a chemically mechanically polished (CMP) prepared Fe₃O₄(111) in hydrated conditions that resulted in a 2-surface termination; 70% oxygen-octahedral iron : 30% oxygen-tetrahedral-octahedral-tetrahedral iron.  To better control and understand how the surface structure/composition changes, electrochemical impedance spectroscopy (EIS) is used where the resultant surface is characterized using in-situ CTR and ex-situ atomic force microscopy (AFM).  EIS results show the oxidized surface has similar resistance to the reduced surface with no apparent changes in the CTR rods; however the AFM images show the formation of globules on the surface.  The terminating surface structures of reduced and oxidized Fe₃O₄(111) surfaces and implications on the surface reactivity will be discussed.