Previous studies of supercritical three-dimensional mixing layers are reviewed to derive a unified understanding of supercritical turbulence and mixing. These studies consisted of Direct Numerical Simulations of mixing layers having initially a single chemical species in each of the two free streams. Each mixing layer was initially perturbed, which led to a double pairing of four initial spanwise vortices. These pairings yielded in each case an ultimate vortex within which small scales proliferated, resulting in a state having turbulence characteristics, called a transitional state. The evolution of the layer to this transitional state and the state itself were previously analyzed to elucidate the features of supercritical turbulence and mixing. This analysis is here used to classify those supercritical turbulent mixing characteristics that are species-system independent or species-system dependent. Finally, comments are offered on future prospects of developing small-scale models particularly suited for Large Eddy Simulations of supercritical turbulent mixing.