Ovelian — Oval-cut gemstones and diamonds as a buying | ovelian.com
Explains carat spread and compares oval, round and other fancy cuts on face-up size per carat.
Carat weight measures mass, not size. Two stones of identical carat weight can present very different face-up areas, because the outline and the depth distribute that mass differently. The visible footprint — face-up area — is what the eye actually reads as size.
Because of their shape, ovals show roughly 10 to 15 percent more face-up area per carat than a round of the same weight. The round brilliant is cut to a standard depth that concentrates mass below the girdle; an oval spreads more of that mass outward along its outline.
The spread advantage is largest at the shorter end of the ratio band, near 1.30 to 1.40, where the stone widens rather than lengthens. Push the ratio to 1.50 and the extra footprint becomes length instead of width, which reads differently on the hand even though the area is comparable.
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Spread is not brilliance. A stone that covers 15 percent more area but leaks light through a shallow pavilion will look duller than its footprint suggests, which is why the bow-tie check belongs in the same decision as the size comparison.
Colour interacts with spread as well: larger tables and elongated outlines make body colour read more strongly, so an oval often needs one colour grade higher than a round to look the same. A larger apparent size therefore carries a colour cost unless the grade is adjusted.
When comparing cuts side by side, compare face-up area at equal carat weight, then judge colour and light return separately. The size advantage is real and measurable; it has to be confirmed against colour and bow-tie before it counts as value.
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