The modern day round brilliant cut diamond came as a result of decades of diamond cutting evolution and was the direct descendant of the transitional cut diamond.
When were transitional cut diamonds invented?
With the advent of new technology in the 1920s an effort began to take shape to create a standardized round cut diamond. The old European diamond began to "transition" to what some call early modern cuts or early American cuts i.e. the transitional cut diamond. Transitional cut diamonds are most often seen in jewelry from the 1930s to the 1940s.
How do transitional cut diamonds look?
Symmetry and consistency was the goal but during this experimental time diamond cutters were still often working by hand. In turn transitional diamonds were cut with varying proportions, angles, and faceting without uniform parameters. They featured larger tables, a lower crown, and a smaller culet than the previous old Euro.