Oval Cut Diamond
Oval Cut Diamond
The Lazare Kaplan modified brilliant in its diamond application
An oval cut diamond is a diamond fashioned in the oval modified brilliant cut introduced by Lazare Kaplan in 1957. The standard pattern carries 56 to 58 facets arranged on the round brilliant template, elongated to give the stone a length-to-width ratio between approximately 1.30 to 1 and 1.70 to 1. The cut combines the brilliance of the round brilliant with the elongated outline that flatters the finger and delivers a face-up size noticeably larger than a round of equal carat weight.
Origin of the cut
Lazare Kaplan, the Antwerp-trained New York cutter who had developed the cleaving plan for the Cullinan diamond in 1908 and who founded Lazare Kaplan International, introduced the modern oval brilliant in 1957. The innovation was not the oval outline — variants had circulated since at least the eighteenth century — but the systematic application of the round brilliant facet pattern to the elongated form, with adjusted angles to retain comparable brilliance and fire. The cut entered the trade slowly, gained traction in the 1970s, and is now the second most popular fancy shape for engagement rings in the North American market.
Faceting and proportion
The standard oval brilliant has a table, eight bezel mains, eight star facets, and sixteen upper girdle facets on the crown; the pavilion carries eight pavilion mains and sixteen lower girdle facets. The culet may be a small flat or, more commonly in modern oval cuts, a keel line where the eight pavilion mains converge along the long axis of the stone. Standard proportions place the table at 53 to 63 percent, the crown angle at 33 to 37 degrees, and the pavilion depth at around 41 to 44 percent.
Length-to-width ratio is the principal proportion variable. The 1.40 to 1.50 to 1 range is the most commonly preferred for engagement settings; ratios under 1.30 read close to round, while ratios above 1.65 read closer to marquise and may be perceived as overly elongated.
The bow-tie
The bow-tie effect — a darker band running across the centre of the stone perpendicular to the long axis — is unique to elongated brilliant cuts and is the principal cut quality consideration for the oval. Some bow-tie is unavoidable in any oval; a small, inconspicuous bow-tie is accepted as part of the cut character, while a pronounced bow-tie is a significant deduction from value. The intensity of the bow-tie is controlled by the pavilion main angles and by the depth-to-spread ratio; the GIA cut report does not currently issue a comprehensive cut grade for fancy shapes, but the bow-tie is the most consistent cut criticism in the trade.
Apparent size advantage
An oval brilliant displays approximately ten to fifteen percent more table-up face area than a round brilliant of identical carat weight. The advantage rises slightly with longer length-to-width ratios. For a one-carat stone, the spread difference can amount to one millimetre or more in the long axis, which is visually significant in a ring setting and is one of the principal commercial drivers of oval cut popularity.
4Cs grading
Oval-cut diamonds are graded by GIA and other laboratories under the same 4Cs as rounds: carat weight, colour, clarity, and cut. The cut report issued for fancy shapes documents proportion measurements, polish, and symmetry, but does not currently assign an overall cut grade. Buyers should request the polish and symmetry grades and should evaluate the bow-tie and outline directly through the laboratory's clarity photograph.
Colour considerations: ovals tend to show colour slightly more than rounds of identical grade, particularly in the bow-tie zone, and the trade typically specifies one colour grade better in oval than in round for the same setting. Clarity considerations: inclusions in the centre of the table are visible because the bow-tie zone draws the eye there.
In the trade
Oval engagement diamonds have moved from a niche shape in the 1980s to one of the leading fancy shapes in the contemporary North American market, with celebrity-led demand and the apparent-size advantage as the principal drivers. Pricing per carat for oval cuts runs at a discount of approximately ten to twenty percent against round brilliants of comparable specification, although the highest-quality ovals at the top of the market have narrowed that gap.