Abstract: A dry washer for separating small high density particles such as gold from a mixture of high and low density material. A rotatable impeller in a cylindrical chamber draws in air and mixed particles, such as sand, and fractures the larger particles. The mixture of air and particles passes to a helical conduit having a perforated partition spaced from the outer wall so that high density particles pass through the wall under centrifugal forces. The particles are passed from the helical conduit to an inclined upper trough including an air permeable floor and riffles or the like to retain the high density particles. Air flow from the helical conduit is directed to a lower trough below the trough. A damper at the end of the lower trough causes air to pass through the air permeable floor and blow away fine low density particles. Dust and air from the trough assembly is passed to an elongated cover to collect the fine, low density, particles.