Proton-induced x-ray emission is suitable for the analysis of thick obsidian samples and artifacts with no special treatment other than washing prior to mounting in a sample chamber vacuum system. X-ray spectra observed with unfiltered and with plastic or pinhole filters are compared. By using a pinhole filter and a single measurement of approximate 4-minute duration followed by thick-target yield calculations, a fit to the observed spectra gives concentrations of such elements as K, Ca, Ti, V, Mn, Fe, Rb, Y, Sr, Zr, Nb, Ta, and Pb. Results for selected source samples from the Pacific region show that the technique provides a suitable method for distinguishing between many of the sources. -- AATA