Typical specimens of Australite (tektite) glass have been studied for such properties as expansivity, annealing temperature, chemical durability over an extended pH range, hygroscopicity, electrode pH response, heterogeneous equilibria at the liquid-solid interface, and spectral transmittance to ultraviolet, visible, and infrared radiations. The results obtained on this glass, supposedly of extra-terrestrial origin, have been compared with similar data obtained on obsidian glass, from Yellowstone Park, and some present-day industrial, optical, and natural glasses. The comparison showed the Australite specimens to be distinctly different from the obsidian, the optical glasses, and the industrial glasses. High softening temperature (approximately 175°C higher than Pyrex 7740), intermediate expansivity, good chemical durability, and low electrode pH response showed the Australite glass to be generally superior. The spectral transmittance was inhibited throughout the ultra violet, visible, and infrared regions by the presence of coloring oxides such as iron, chromium, copper, nickel, and manganese.