Just a short Did You Know article about the early diamond cuts in Europe. In the 17th century there are examples of some quite curious diamond cuts for rings. A rough diamond often was extracted having an octahedral shape: Two pyramids attached to each other at the base, as seen here:
The diamond was not necessarily cut into a different shape. The diamond setter was content to polishing the stone and perhaps grinding it slightly, before setting it into a ring, still in its original octahedral shape as in this example below.
It looks quite dangerous, doesn’t it? Due to the hardness of the stone, you can imagine scratching many surfaces with this ring and it does look rather unsafe for people as well ! This ring is what is called a claw setting ring with a pointed or facetted diamond, and they were very popular in Europe in the 17th century. The example above is in the Museum Für Angewandte Kunst (Museum of Applied Arts), in Cologne.
Purportedly to make the ring more inoffensive, in a different example below, the apex of the diamond pyramid has been cut, so it presents a table, thus avoiding the incredibly sharp edge!
Source: A SPARKLING AGE, 17th-Century Diamond Jewellery (1993, Diamantmuseum, Antwerp)