Permanent powder mounts were prepared for X‐ray spectrographic analysis by molding bakelite powder at 24,000 psi and heating to 110C. Spraying with clear acrylic resin maintains surface permanency for non‐clayey samples. Standard curves for Si, Al, Fe, K, Ca, and Ti prepared with USGS and NBS rock powders were used to determine that two distinct textural layers of Mazama pumice had similar major element contents. Ground pumiceous lapilli from the weathered AC horizon (20–30 cm depth) had 4% less Ca, 4% less Si, 8% less K, 9% more Ti, 12% more Al, and 16% more Fe than unweathered pumice in the C1 and C2 horizons.