A round brilliant returns more light to the eye than any other diamond shape, which is why roughly half of all engagement rings sold in the UK use one. At Luma our settings start at £670 and a finished round ring starts from around £820, because you choose your certified lab grown diamond separately and we price it when you select it. We make every ring to order in our Hatton Garden workshop, set only IGI certified stones, and hallmark each one in the UK. The 57 facets of a round brilliant are cut specifically to maximise return of light, so this is the shape where cut quality matters most and where a well cut lab grown stone is hardest to tell from anything else on the finger.
Settings for a round centre stone
AnoukClassic solitaireSetting from £670
MarenCathedral, plain bandSetting from £740
AmaraHidden halo, pavéSetting from £790
OdetteHalo, pavé bandSetting from £1,100
Each price is for the setting. You choose your certified lab grown diamond separately and we price it live when you select it, so the total depends on the stone. See all round engagement rings.
Why round is the default, and when it should not be
The round brilliant exists for one reason: to send as much light back at you as possible. Its facet pattern was worked out mathematically for exactly that, and no other shape beats it for brightness. If sparkle is the priority, this is the shape.
The trade off is size on the finger. A round holds more of its weight in the depth of the stone than an elongated shape does, so a 1ct round covers less finger than a 1ct oval or pear of the same weight. If you want the ring to read as large for the money, an elongated cut will do it better. If you want it to read as bright, round wins.
Where to spend on a round diamond
Cut, then clarity, then carat. That order matters more here than in any other shape.
Because a round brilliant is judged on how it handles light, a poorly cut one looks dull no matter how large or how clean it is. A well cut 1ct will out sparkle a badly cut 1.5ct every time, and cost less. Once cut is settled, an eye clean stone is enough. Paying for a clarity grade you cannot see without a loupe is money that would be better spent on the cut or the size.
Colour is where lab grown gives you the most freedom. Because the stone costs a fraction of a mined equivalent, moving up a colour grade or two is affordable in a way it usually is not, and in a white metal setting that difference is visible.
Which settings suit a round centre
Round is the most flexible shape we set, because its symmetry works with everything.
A plain solitaire such as the Anouk is the purest version and puts every pound into the stone. A cathedral setting like the Maren lifts the diamond slightly so more light enters from the side.
A halo works particularly well around a round centre because the surrounding stones match its symmetry, which is why the Odette reads so cleanly. A hidden halo like the Amara tucks that ring of stones underneath, so the ring stays simple from above and reveals detail from the side.
A trilogy with round shoulders is the other classic pairing, and it adds width without adding height.
What a round ring costs at Luma
Settings run from £670 for the Anouk up to around £2,400 for our most involved designs, with most sitting between £670 and £1,200. The setting price climbs with the carat it is built to hold, since a larger stone needs more metal and more work. Your diamond is priced separately on top, so a finished round ring starts from around £820 and most land between roughly £820 and £3,000.
Common questions
How much does a round lab grown diamond engagement ring cost in the UK?
At Luma settings start at £670 and we price your IGI certified lab grown diamond separately when you choose it, so a finished round ring starts from around £820. Most land between roughly £820 and £3,000 depending on the carat, colour and clarity. The same specification in a mined diamond typically costs several times more.
Is a round brilliant the best shape for a lab grown diamond?
It is the brightest, which makes it the safest choice. A round brilliant is cut to return the maximum amount of light, and because a lab grown diamond is the same material as a mined one with the same refractive index, it performs identically. If sparkle matters most to you, round is the shape.
Does a round diamond look smaller than other shapes?
Slightly, at the same carat weight. A round carries more of its weight in depth, so it covers less of the finger than an oval, pear or marquise of equal weight. Because a lab grown stone costs far less, the usual answer is simply to buy a larger round rather than compromise on the shape you want.
What should I prioritise when choosing a round diamond?
Cut first, always. A round brilliant lives or dies on how well it is cut, and a poorly cut stone looks dull regardless of size or clarity. After that, choose an eye clean clarity rather than paying for a grade only a loupe can see, and put whatever is left into carat or colour.
See the full range on our round engagement rings collection, or book a studio consultation at our Hatton Garden workshop and we will build to your budget.
Shop by shape: round, oval, pear and emerald lab grown engagement rings.