This ring presents two rare surviving examples of ‘knob-cut’ diamonds and a 17th century seven-stone ring setting. The ‘knob-cut’ was a development of the classic pyramidal-cut by eliminating the main point and replacing it with a very small table. This particular cut was popular in Europe from 14th to 17th century. It was sometimes referred to as ‘nail-cut’, in some inventories, as the crown looked like the head of an antique nail. Very few ‘knob-cut’ diamonds have survived as eventually, most of them were re-fashioned into ‘table cut’ diamonds.
The ‘knob-cut’ diamonds are set in a classic 17th century ‘seven-stone’ ring. This specific ring setting would have three small diamonds set on either side of a larger central stone, placed lozenge-wise. The gold ring would be engraved with foliage or scrolls on the shoulders. The reverse of the bezels would have been applied with black and white enameling, sometimes figuring flowers, rosettes or acanthus ornaments.