Some series of granitic rock samples have been investigated by the aid of minicomputer spectral analysis after neutron activation. Maintaining an optimal relation between measurement time, precision of analysis, and a high sample throughout as well as a great number of elements, the concentrations of some elements have been determined. The total set of elements should than be reduced by statistical feature extraction in order to obtain an optimal set of elements with the same discrimination power. The presented paper especially concerns with the relation of tin-tungsten ore deposits near the areas of high differentiated granitic rocks (Variscian age).