We always enjoy singing the praises of old cut diamonds. We love these sparkly stones because they aren’t perfect, and were cut by hand with great care using the technologies of their day.
In the 19th century to the early 20th century, from whence most of our antique diamond jewelry hails, we mainly see two types of diamond cuts: the old mine cut and the old European cut. They lack the mathematical, machine-cut precision you see in modern gems. However, old world lapidaries knew what they were doing. They studied the rough mined diamond and cut stones to maximize their brilliance as best they could.
Old mine cut or antique cushion cut diamonds are not fully round. They characteristically have a high crown angle on the top. Because lapidaries lacked the technology to bring the pavilion (the pointy end) to a point, they made the bottom of the diamond its own facet, called the “culet.”
Old European cut diamonds represent an evolution of this cutting style, and started appearing in the late 19th century. Diamonds became more round, and more facets were cut to increase sparkle. The tops, or crown angles, were made shallower, and diamond cutters came closer and closer to bringing diamond pavilions to a perfect point. Thus, culets became smaller and smaller; eventually technology rendered them nonexistent. This is seen in modern brilliant cut diamonds.
One of the easiest ways to guess if your diamond is antique just requires your naked eye. Stare right down the center of the stone. Old mine cuts will look like they have a little dot in the center because you can see down to the culet facet. You can also see the tiny culets of old European cut diamonds, though sometimes you need a jeweler’s loupe because the pavilion comes close to a perfect point.