A user-oriented command language is developed to provide direct control over the computation and output of the standard CIPW norm. A user-supplied input format for the oxide values may be given or a standard CIPW Rock Analysis format may be used. Once the oxide values have been read by the computer, these values may be manipulated by the user and the 'norm' recalculated on the basis of the manipulated or 'adjusted' values. Additional output capabilities include tabular listing of computed values, summary listings suitable for publication, x-y plots, and ternary diagrams. As many as 20 rock analysis cards may be processed as a group. Any number of such groups may be processed in any one computer run.