We report on THz spectra of RDX obtained from various domestic and international sources. The observed spectral differences can be traced to the method of RDX manufacture. Depending on the method of manufacture, the resulting energetic material will contain imperfections within the crystal such as voids, solvent trapped within the voids, crystalline dislocations, explosive mixtures and co-crystallization of other energetic byproducts. Additionally, neat energetic material crystallites often range from tens to hundreds of microns. To investigate these phenomena, transmission and reflection mode THz spectroscopy was performed. The resulting spectral differences are interpreted in an attempt to identify material and contaminant effects.