The emanating Ra contents of background and contaminated soils were measured using commercial alpha-track detectors sealed with samples in glass Mason jars for a 179-day period. The observed track densities were linearly correlated with independently measured emanating Ra contents using gamma assays for total Ra and Rn emanation measurements. The simple new jar test exhibits high sensitivity and requires minimal equipment and user's training. It has applications in indoor Rn and building material studies as well as geochemical exploration.-Authors