Old Mine Cut diamonds are a type of diamond cut that were popular in the 18th and 19th centuries. They are a predecessor to modern round brilliant cut diamonds and were often used in antique jewellery.
Old Mine Cut diamonds have a cushion-shaped outline with a high crown, small table, and large culet.
The culet is the small facet on the bottom of a diamond, directly opposite the table (the large flat facet on the top).
In modern diamond cutting, the culet is typically very small or even non-existent, as it is desirable for the diamond to come to a point at the bottom to maximize light performance.
However, in older diamond cuts, such as the Old Mine Cut and the Old European Cut, the culet was often larger, sometimes even visible to the naked eye.
Back then a larger culet allowed the diamond cutter to retain more of the diamond's original weight, as it was difficult to cut a diamond perfectly to a point at the bottom.
A large culet can also affect a diamond's appearance, as it can create a "hole" in the center of the diamond that can be seen when viewed from certain angles. However, some people find this characteristic to be charming and very desirable, especially in antique or vintage diamonds.
They typically old mine cuts (OMC) have 58 facets, including a large, flat top facet known as the table. They were cut by hand, so each diamond is unique, with slight variations in shape and facet arrangement.
Apart from the desired culét, one of the defining features of Old Mine Cut diamonds is their high crown, which makes them appear larger than modern diamonds of the same carat weight.
However, their uniqueness and history make them highly sought after by collectors and jewelry enthusiasts today.