A program for treating large numbers of qualitative and/or quantitative geological thin section data has been developcd. Data are coded, stored in a direct access data bank, and extracted selectively for treatment. The system is easy to handle and flexible, that is the user can choose descriptive attributes (variables) and select parameters for different computational operations. The codification and program can be applied to all rock type. The treatment includes: Loading of data bank, Updating of data bank, Selection of sample and variables, Edition of samples, Variable distribution in geological sections, Histograms, Scatter diagrams, Association analysis and Correspondence analysis.