This note describes a simple and rapid method of preparing glasses suitable for electron microprobe analysis from powdered silicate rock specimens. Rock powder (100–200 mg, less than #200 mesh) is loaded into platinum crucibles fashioned from thin foil (1 mil or less). The powder is then melted in the graphite furnace of a flameless atomic absorption spectrophotometer by heating at 1700°C for one minute. The Pt crucibles filled with glass are conveniently mounted with five or more on a single mount, for subsequent preparation and polishing for analysis. The glasses are analyzed for major elements with an automated electron microprobe. For samples up to at least 60 wt.% SiO2, homogeneous glasses are obtained. Because of the short heating interval and very short heat-up and cool-down times, no loss of alkalis or iron occurs. The method is rapid, inexpensive, relatively free from possibility of contamination, and is particularly well-suited for small samples.