Modes, total rock chemistry (including a range of trace elements) and mineral analyses are presented for two selected rocks from the Yeoval (Australia) high-K diorite complex. This and other data show that the high-K diorites may definitely be grouped with calc-alkaline rocks and that the high-K diorites and low-Si diorites are almost identical in chemistry to their fine-grained equivalents. Comparisons of the data are made with other similar rock groups. Criticism is made of the presently used mineralogical classification of diorites and in particular of those diorites rich in potassium. A chemical classification of diorites identical to that used for andesites is proposed.