Abstract Alluvial fans, valley fills and debris cones represent economically significant, natural aggregate resources in the alpine regions of Austria. Due to continual erosion they constitute renewable sources of sand and gravel. However, knowledge of their petrographic properties and resulting aggregate quality is scant. An automated evaluation method was developed to estimate petrographic characteristics and predict resource suitability. This method makes use of the fact that the properties of a gravel deposit depend on the morphology and geology of the provenance area. Area percentages of geological units in the source area were expected to mirror the litho-spectrum of the gravel resource. Petrographic analysis of 13 field samples shows that this is indeed the case. Discrepancies amount to 0–10%; larger deviations occur for grain size fractions <2 mm in the presence of soft rock types such as mica-schist or paragneiss. Forecasts of aggregate quality on the basis of lithological composition and grain size characteristics were compared to operational data of five gravel pits. The actual usage of the material agrees with predictions in four out of the five cases.