Geosientists in academia and industry use ternary plots to characterize the composition of rock types. A common example is the quartz-feldspar-lithic relationship in sedimentary rocks that has implications for provenance of sediment, distance traveled and potential for diagenesis. Clay and gas (oxygen-methane-inert gas) compositions are also plotted on ternary diagrams.
The plotting capabilities in Pro appear to be a significant improvement over ArcMap. Please consider adding ternary graphing capabilities to our options.