Aluminum nanoparticles are an intriguing material because of their high reactivity and high energy density, making them ideal for propellant materials such as rocket fuel. In addition, nanoaluminum is also a promising abundant, low cost material for plasmonic applications with a plasmonic response that can extend from the visible region of the light spectrum down to ultraviolet wavelengths of light. Nonthermal plasmas are a promising tool for synthesizing nanocrystalline materials without the need for high temperatures or solvents. Their ability to add electrons to the surface of nanoparticles within the plasma helps reduce agglomeration and form aerosols with tighter size distributions than other competing aerosol synthesis techniques. Nanoparticles containing crystalline elemental aluminum were synthesized using a nonthermal plasma containing trimethylaluminum (TMA) vapor, argon and hydrogen gases. The percentage of hydrogen flowing with respect to total gas flow was required to be at least 70% in order to form crystalline aluminum. In addition the ratio of H2 to TMA flow rates needed to be a minimum of 60. 7% of the nanoparticles' aluminum atoms were in elemental aluminum form with the remaining ones in the form of alumina (Al2O3) or an aluminum hydroxide according characterization by air-free X-ray photoelectron spectroscopy. Air-free X-ray diffraction of the nanoparticles indicated the average crystallite size of the elemental aluminum in the particles was on the other of a few nanometers.