Cushion Lab Grown Diamonds

What is a cushion lab grown diamond?

A cushion lab grown diamond is a square or rectangular stone with softly curved corners and a facet pattern that produces broad, open flashes of light rather than the tight scintillation of a round brilliant. It is grown in a controlled laboratory environment using either high-pressure high-temperature (HPHT) or chemical vapour deposition (CVD) methods, producing a diamond that is chemically and optically identical to a mined stone. The cushion shape has been in continuous use since the nineteenth century and its vintage character sits comfortably in both antique-inspired and contemporary settings. Lab origin does not alter the cut, the facet arrangement, or the way the cushion's characteristic pillow-like profile distributes light — it only changes where the crystal grew.

How to choose a cushion lab grown diamond: cut, ratio and clarity

The most important variable in a cushion lab grown diamond is the length-to-width ratio. A ratio close to 1.00:1 reads as square; a ratio of 1.15:1 to 1.30:1 reads as a softly elongated rectangle that can make a finger appear longer. Cushion cuts come in two broad facet styles: the 'chunky' cushion, which has fewer, larger facets and produces broad candlelight-style flashes, and the 'crushed-ice' cushion, which breaks light into many smaller points and reads more like a round brilliant from a distance. Because cushion cuts tend to retain colour in the corners, a near-colourless grade of G or H is generally sufficient in a white-metal setting, allowing budget to be redirected toward carat weight — an area where lab grown origin already offers a significant size advantage over equivalent natural-diamond spend. Every cushion lab grown diamond here is certified by GIA, HRD or IGI, with cut, colour, clarity and carat recorded on the certificate.

What does a cushion lab grown diamond cost in the UK?

Cushion lab grown diamonds are consistently priced well below equivalent mined cushion stones of the same carat weight, colour and clarity. The cost difference allows buyers to step up meaningfully in carat weight — for example, choosing a 1.5ct or 2.0ct cushion lab grown diamond at a price that a 0.75ct or 1.0ct mined cushion would otherwise occupy. Bridebook's 2026 UK average engagement ring spend of £2,247 provides useful context: a cushion lab grown diamond can put a significantly larger, well-specified stone within or near that budget. Price per carat varies with certification grade, the precise facet style (crushed-ice cushions often attract a small premium due to cutting complexity), and colour and clarity grade. All stones are available loose with complimentary insured UK delivery, and a 30-day return window with no questions and no exclusions applies to every loose purchase.

How are cushion lab grown diamonds certified and sourced?

Every cushion lab grown diamond in this collection carries a certificate from GIA, HRD or IGI — the three internationally recognised grading laboratories — confirming the stone's origin, dimensions, and 4C grades. Lab grown origin is declared on every certificate, and the grading methodology is identical to that applied to mined diamonds. Stones are sourced from established lab grown producers whose processes meet responsible production standards. When a loose cushion lab grown diamond is selected and set into one of our rings, the finished piece is hallmarked at the London Assay Office, and the 7–14 working day lead time for ring production then applies.

Which settings suit a cushion lab grown diamond?

The cushion shape's soft corners and broad table work well across a range of settings. A four-claw solitaire maximises light entering the stone and keeps the cushion's outline clearly visible. A halo of smaller diamonds draws the eye and can make the cushion appear larger, though it also frames the stone more tightly — an approach that tends to suit the chunky-facet cushion more than the crushed-ice variety, where the halo can visually compete with the stone's own internal pattern. A bezel or half-bezel setting suits the cushion well for daily wear, anchoring the curved corners securely. In terms of metal, platinum and white gold are neutral backdrops that emphasise colour grades of F through H; yellow or rose gold can complement a warmer G or H grade and suit the cushion's inherently vintage character. All settings are available in platinum or gold.