An argon plasma jet source of recent design is applied to multiple element spectrographic analysis of geological materials. The source is characterized in terms of accuracy of analysis and repeatability of measurements obtained from spectra from a large region of the plasma. Results of analyses for Al, Ca, Fe, Mg, Si, and Ti in geochemical reference samples, for Ti in lunar basalts, gabbros, and soils, and for the SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ratio in mordenite from geodes are presented. The effective temperature of the plasma region used for analytical measurements is 4670 ± 50°K. Use of control samples is recommended to improve accuracy of analysis.
D. W. Golightly and J. L. Harris, "Spectrographic Analysis of Geological Materials with an Argon Plasma Jet," Appl. Spectrosc. 29, 233-240 (1975)