Radiant Cut vs Cushion Cut Lab Grown Diamonds: Price Difference and Value Explained

The $200-Per-Carat Gap Nobody Talks About

Spend an afternoon comparing IGI-certified lab grown diamonds at F/VS1 across multiple retailers and a quiet pattern shows up: radiant cuts consistently price out roughly $200 per carat above cushion cuts at equivalent grades. Janine Jewels, a Toronto-based retailer tracking its own IGI inventory, published figures of approximately $2,500/ct for radiant versus $2,300/ct for cushion at F/VS1 in early 2026. That gap is not enormous, on a 1.5-carat stone it works out to a $300 difference, but it is consistent enough across the market to be meaningful when you are deciding between two shapes you genuinely like.

The reason for the spread comes down to two things. First, radiant cuts carry 70 facets compared to the cushion’s more typical 58, and that additional faceting demands more precision from the cutter. Second, demand dynamics: radiant cuts have seen price volatility in 2026 as Indian CVD production has increased supply, but the shape still commands a modest premium over cushion because buyers associate its crushed-ice sparkle with a more modern, high-brilliance aesthetic. Cushions, by contrast, retain more of their rough weight below the girdle, which makes them slightly more yield-efficient to cut, and that efficiency tends to pass through to price.

So the cushion is cheaper per carat. But cheaper per carat is not the same as better value per carat. That distinction is where this comparison gets interesting.

Which One Actually Looks Bigger?

This is the question that drives most of the search traffic around these two shapes, and the geometry here is specific enough to be worth quoting precisely.

Radiant cuts are engineered with a shallower profile, which pushes more of the stone’s carat weight toward the table, the flat top surface you see when the diamond is set in a ring. Elongated cushions, by contrast, carry more of their weight in the pavilion (the belly of the stone below the girdle), so a measurable portion of the carat weight is hidden beneath the setting. The practical result: a 1.5-carat radiant can measure approximately 8.5 mm × 6.55 mm face-up, while a 1.5-carat elongated cushion of similar proportions tends to run closer to 8 mm × 7 mm. The radiant is longer and slimmer; the cushion is wider but shorter. Neither is objectively larger, they just distribute their footprint differently.

But the radiant wins on the specific question of perceived size. Its straight beveled edges and cropped corners create a clean rectangular border that reads as more expansive to the eye. The cushion’s rounded corners, while softer and arguably more romantic, interrupt that silhouette and make the stone appear slightly smaller at the same carat weight. For buyers whose primary goal is maximum visual size per dollar, the radiant delivers, even though it costs more per carat.

This is the core tension in the comparison. The cushion costs less per carat. The radiant looks larger per carat. Whether that size advantage justifies the $200/ct premium depends entirely on what you are optimizing for.

Where the Price Gap Narrows, and Where It Widens

At 1 carat, the $200/ct gap between radiant and cushion is relatively painless: you are talking about a $200 difference on a stone that might retail between $900 and $1,400 depending on color and clarity. But the gap compounds as carat weight increases, because lab grown diamond pricing is not linear. StoneAlgo’s market index, which tracks daily retail prices across more than 750,000 lab grown diamonds, shows that a 2-carat stone does not simply cost twice a 1-carat stone, the price per carat rises with size because growing a larger, inclusion-free crystal takes significantly more time and carries higher failure risk. At 2 carats, a $200/ct premium translates to $400 of additional spend. At 3 carats, it becomes $600. Buyers working with a fixed budget who want the largest possible face-up stone should factor this scaling effect into their math.

Color and clarity grades interact with the shape premium too. Both radiant and cushion cuts are exceptionally good at masking inclusions, the radiant’s crushed-ice faceting breaks up light so aggressively that SI1 stones are frequently eye-clean, and the cushion’s broader facets scatter color warmth in a way that makes G or H color grades look near-colorless in most lighting. This means buyers in both categories can often step down from F/VS1 to H/VS2 and lose nothing visible to the naked eye while saving 20–30% on the stone. That savings dwarfs the $200/ct shape premium entirely. The practical takeaway: optimizing your color and clarity grades will do more for your per-carat value than choosing one shape over the other.

Certification also moves the needle. IGI-certified lab grown diamonds are the market standard for this category, and IGI’s pricing tends to run 8–12% below equivalent GIA-certified stones, not because the diamonds differ in quality, but because GIA’s brand carries a resale-confidence premium that most engagement ring buyers do not need. Both radiant and cushion cuts at Ouros Jewels are available with IGI certification, which keeps pricing transparent and grading consistent across the board.

Who Should Choose Which

A buyer who wants the sharpest possible visual impact, someone building a solitaire or a three-stone ring where the center stone is the entire statement, will probably prefer the radiant. Its straight geometric edges read boldly on the finger, its 70-facet pattern produces the kind of glittery, high-frequency sparkle that photographs well and catches light under office fluorescents as readily as candlelight, and its elongated form flatters most hand shapes by adding apparent length to the finger. The radiant is also the more versatile shape for matching side stones: its 45-degree cropped corners sit cleanly alongside both tapered baguettes and round brilliants, which makes it a natural anchor for a three-stone setting.

The cushion, on the other hand, tends to suit buyers who are drawn to something with more warmth and character. Its broader facets produce vivid bursts of prismatic color, what gemologists call fire, that look particularly beautiful in lower-light settings and pair naturally with yellow or rose gold. The rounded corners are gentler on the eye and lend themselves to halo and hidden halo settings where the frame of accent stones amplifies the center stone’s apparent size. A well-chosen halo around a cushion cut can close the perceived-size gap with a radiant almost entirely, which is worth considering if you prefer the cushion’s aesthetic but are worried about losing visual impact.

Both shapes are durable for daily wear. The radiant’s beveled corners reduce chipping risk compared to sharper shapes like princess cuts, and the cushion’s naturally rounded edges are similarly forgiving. Neither requires special care beyond what any fine diamond ring needs.

For buyers at Ouros Jewels specifically, both shapes are available as IGI-certified loose lab grown diamonds that can be set into custom engagement rings or selected from existing settings. The spans a wide range of carat weights and colors, including fancy vivid pinks and yellows for buyers who want something beyond the standard colorless range. The  covers classic cushion brilliant and elongated cushion options, with the same IGI certification and direct-to-consumer pricing that removes the traditional retail markup.

The Honest Recommendation

At equal IGI grades, the radiant costs about 8–9% more per carat than the cushion and delivers a measurably larger face-up appearance in return. Whether that trade-off makes sense depends on your setting choice and your aesthetic priorities, not on any abstract notion of one shape being objectively superior.

If you are building a solitaire or three-stone ring and want the center stone to read as large as possible, the radiant is worth the premium. If you are planning a halo setting, where the accent stones will add apparent size regardless of the center stone’s shape, the cushion offers equivalent visual impact at a lower per-carat cost, and the savings can go toward a higher carat weight or better color grade.

The one thing that matters more than either of these shape-level decisions is cut quality. A radiant or cushion with a poor cut will look dull and lifeless regardless of its carat weight. An excellent cut in either shape, at a practical color grade like G or H and a VS2 or SI1 clarity, will outperform a higher-graded stone with mediocre proportions every single time. That is where the real value lives, not in the $200/ct gap between shapes, but in the cut quality that determines whether the stone actually performs.