The Radiant Cut Diamond is considered the grandfather of the modern day fancy cut with a history of over 20 years. The popularity of the diamond comes from the fact that it was the first diamond to have the pavilion faceted. The radiant cut, also known by the terms a cut-cornered and also by GIA as a square modified brilliant, typically has 70 facets. The radiant cut of diamond is a square shaped cut however as sharp edges are a point of weakness in the gem, cutters have truncated the edges.
The appearance of the diamond is of a very unique sparkle this comes from the fact it is a mixed cut, thereby having characteristics of both the step cut diamonds and of the brilliant cut diamonds. The defining characteristic however, is the truncating of the corners. It is this which enables it to be easily distinguished from the princess cut another mixed cut.
Since the popularisation of the princess the radiant cut has seen its own popularity fall somewhat. This is down to the princess cuts higher fire and brilliance than that of the radiant cut. They are both mixed cuts and both also are referred to as the square modified brilliant, however the princess has fewer facets and is without truncated edges.
When buying a radiant cut diamond it is recommended that you try to purchase one within the ratio of 1.5 as this is will result in the greatest sparkle. It has however became more and more popular over recent years to have a squarer shape which would obviously take the ratio down nearer to one.
The main use of the radiant diamond is as the centre of a ring typically with round brilliants or baguettes flanking. The strong appearance of the diamond makes it more versatile than either the emerald or princess cut its main rivals.