An aggregate washing and classification system incorporates into a water-filled receptacle a sand classifier and one or more rotating augers. The augers are wrapped with screens or perforated walls that are fixed relative to the augers. The size of the perforations may be chosen to selectively sift particular sizes of gravel and rock, and if the perforations increase in size along the length of the augers, either continuously or discontinuously, the material which passes through the perforations will likewise increase in size with greater travel through the auger passageway. Consequently, a set of rock bins may be provided adjacent to the auger outlet, for collecting various sizes of larger aggregate, such as washed rocks. Sand will typically be permitted to pass through the screen perforations near the aggregate inlet. Once outside of the auger and screens, the sand will drop directly into a sand classifier, which is conveniently located directly below the augers and adjacent to the material inlet. Fresh water is pumped into the bottoms of the rock bins, and flows counter to the aggregate passing through the augers. The counter-flow keeps the rock bins clean, and the flow of water adjacent and counter to the material inlet is used to extract and discharge low-density matter from the aggregate inlet. The entire system is desirably incorporated into a single land vehicle for transport to aggregate sources, such as gravel pits and the like, where the finest grades of aggregate may be rapidly prepared.