The oval cut is a variation on the round-brilliant popularised during the 1960s by Lazare Kaplan, a nephew of Marcel Tolkowsky. This shape of this cut appeals to buyers looking for a stone that is traditional in appearance but not readily common; like other fancy cuts, it accounts for a small percentage of larger diamond sales.
The classic oval cut will have the same number of facets as a round brilliant: a table, 32 crown facets and 24 pavilion facets with or without a culet. The usual placement of crown facets directly above the pavilion produces a "bow-tie" effect.
This may be reduced or removed by the cutter twisting the pavilion facets one phase out of alignment. Other cutting variations are possible - one is having half-moon facets along the sides of the stone, resulting in less pavilion angle variation between the sides and the ends of the stone and improving both the yield from the rough diamond and brilliance.
An oval-cut diamond should be in proportion - not too short and squat, nor long and skinny.
The general rule is that the length should be one and a half times the width. Taking this into account and calculating the optimum depth percentage - depth divided by width then multiplied by a hundred - one should expect a well-proportioned oval cut to be deeper than a round brilliant; however, table and depth percentages don't seem to aid when selecting oval diamonds for cutting quality.
There are many benefits for the consumer in purchasing an oval-cut diamond. Like the marquise, a ring set with an oval-cut diamond is said to lengthen the finger and make it appear slender, but the more traditional shape of the oval could give it broader appeal than that of the marquise as it has a very good spread or size for weight.
On the downside, an oval cut presents some design restrictions, as it is difficult to match with other cuts. In particular, care should be taken about placing similar-sized round brilliants beside an oval as the oval's lesser brilliance can make it pale by comparison. As such, when it comes to rings, oval cuts are generally employed as a solitaire, or teamed with other ovals, half moons or contrasting cuts like tapered baguettes in three-stone rings.
Considered to be close to an egg shape, the oval cut is said to represent fertility. Perhaps Tom Cruise was aware of this when, after years of allegations regarding his fertility, he presented partner Katie Holmes with a 4.5-carat, oval-cut diamond ring. In return, Holmes gave Cruise a daughter.
The most famous oval-cut diamonds is, of course, the Koh-i-noor, a diamond so highly sought it was responsible for entire wars.
Crossing from India to England during the mid-19th century, the 189-carat Koh-i-noor was re-cut by the Queen's royal jewellers to the 108.93-carat it is today. It is set into Queen Elizabeth II's coronation crown and rests for all to see in the Tower of London.