|Gemstones and Other Materials
|6.51ct Fancy Dark Yellowish Brown colour IF Old mine cushion cut diamond - with GIA certificate
|22ct yellow gold with maker's mark and London assay marks
|UK finger size S 1/2, US finger size 9.25 (Can be adjusted)
Front centre: 15.2mm
Back centre: 3.7mm
Coloured diamonds or Fancy diamonds as they are also known, have become increasingly popular over recent years and are available in a beautiful range of colours from yellow and pink to blue and green. Colour in diamonds can be caused either by a structural anomaly or by elements such as nitrogen or boron replacing carbon atoms within the crystal structure of the diamonds. In yellow diamonds it is nitrogen which is responsible, and the strength of colour depends on how much of it there is and what form it has taken. When a coloured diamond is graded for certification by the GIA, the saturation of colour will be judged and one of the following grades will be assigned: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Dark and Fancy Deep.
Old mine brilliant cut diamonds are sometimes referred to as old miners or OMBs and are either square or rectangular diamonds with obviously rounded corners and sides. This softened profile is called a cushion shape as the convex edges and curved corners are said to resemble an actual cushion.
The style developed during the 18th century after the discovery of diamonds in Brazil in about 1725. This facilitated experiments in cutting due to the large increase in available stones. Eager as ever to retain as much weight as possible, cutters still followed the overall shape of the rough crystals but now corners became more rounded and the number of facets were increased. The profile proportions of the stones also echoed the rough with the crowns being relatively high and the top table facet generally fairly small. Another typical feature of these stones is the point at the bottom of the stone, known as the culet, which was polished flat.
The discovery of diamonds in South Africa during the late 1860’s coincided with revolutionised mechanical cutting methods. This saw the fashion for new circular cut diamonds begin to replace these cushion shaped stones which then became known as ‘old mine’ diamonds. Today the name ‘old mine brilliant’ still describes a cushion shaped diamond with a small table facet, high crown and polished culet. These features enable old mine cuts to display a huge amount of fire (the coloured flashes of light you see in a diamond) and life.