Gradient-driven mass diffusion, or species separation, is a transport process which can occur in plasma shocks. Experimental observations of this phenomena are difficult to make, but are of interest to ongoing Inertial Confinement Fusion efforts. This body of work describes the results of two major experimental campaigns conducted at Virginia Tech's Experimental Plasma and Propulsion Laboratory to identify species separation in multi-component plasma shocks. A linear plasma-armature railgun forms and accelerates low temperature, high density, supersonic plasma jets, with the collision between two of these jets shown to induce a collisional plasma shock in the first campaign. The second campaign leverages this experimental setup while employing spatially resolved emission spectroscopy alongside collisional radiative modeling to identify species separation within multi-ion-species plasma shocks consisting of argon, aluminum, and nitrogen. These results are some of the first to be performed in a plasma shock with more than two ion species, and can be used for verification and validation of physics models of fusion plasmas. This body of work was supported by the National Science Foundation under Grant No. PHY-1903442. / Doctor of Philosophy / Plasmas represent the fourth state of matter, where enough energy has been imparted onto a gas for ionization to occur, resulting in a quasi-neutral collection of charged and neutral particles that are subject to both hydrodynamic and electrodynamic effects. Shocks can occur in plasmas, which presents as a transition layer where plasma parameters drastically change over a small region of space. Plasmas hold the key to nuclear fusion, with the topic of gradient-driven mass diffusion, or species separation, in plasma shocks being of great interest to large-scale fusion experiments. This body of work performs experimental measurements using a railgun-based plasma source to create plasma shocks with multiple ion species in the laboratory, and ultimately observe this effect of species separation through the use of spatially resolved spectroscopy. To the author's best knowledge, these measurements represent some of the first to be done in a plasma shock with more than two ion species, and can be used to benchmark physics models of plasmas in fusion experiments.