In the mid-17th century cutting styles took a step toward what we are more familiar with in modern cuts. Up until now, the shape if the diamond crystal was apparent in the finished product. With the invention of better diamond finishing equipment, cutters could add more facets to the diamond, and add they did.
The old single cut has almost twice as many facets as the table cut. Removing the corners of the previously square cut produced an octagon shape that begins to take advantage of the dispersive qualities of Diamond. Dispersion is what you might call the fire, or rainbow colors, you see when gazing into a well cut diamond.
The eight facets on top are called the crown facets and the eight on the bottom are called pavillion facets. A culet may or may not be present. Because of these sets of eight facets, sometimes this is also called the Eight Cut.
Modern techniques have introduced a round girdle profile to this cut. Tiny accent diamonds are typically cut in this fashion.
Single cut diamonds can be found surrounding pearls, adorning watch faces, and carpeting vast swaths of pave.
Next time, the evolution of the Modern Brilliant continues with the Old Mine Cut.