Why this page exists
"How big a stone for my budget" is the first question almost every engagement-ring client asks, and the answer for lab-grown has changed so fast that most published guides are out of date within a year. The bands below are UK, 2026, and sourced. They cover the stone. What the commissioning process costs on top is covered by our sister site, commissionedjewellery.com, and we will not duplicate it here.6
Disclosure: this site is published by Lark & Berry, a designer house selling bespoke lab-grown engagement rings. We have an interest in you buying a ring; we have no interest in you overpaying for a stone.
2026 UK price bands for lab-grown diamonds
One UK retailer's published 2026 guide gives these retail ranges for round lab-grown stones, with the mined equivalent alongside:1
| Carat | Lab-grown (UK retail) | Mined, same grades |
|---|---|---|
| 1.00 ct | £1,050 – £3,500 | £4,500 – £8,500 |
| 2.00 ct | £2,500 – £6,500 | £12,000 – £22,000 |
| 3.00 ct | £3,000 – £10,000 | £28,000 – £55,000 |
Two things stand out. First, the lab-grown ranges are wide, because colour, clarity and cut quality still move price a great deal within a carat weight. Second, lab-grown prices rise roughly linearly with size while mined prices rise steeply; that is why the gap is widest at exactly the sizes engagement rings use.
The wholesale picture behind those bands: Edahn Golan's index recorded a 26% average fall in 2025, with 3 carat rounds down 32% year on year but 1.5 carat goods down only 8%.2 Larger stones are getting cheaper faster than smaller ones, and the quarterly decline had narrowed to 4.7% by the end of 2025.2 UK trade commentary reads that as the market nearing a floor.3
Three worked examples
These assume a total ring budget, not a loose-stone budget. Figures are illustrative, drawn from the bands above and from our own 2026 bench experience; your quote will differ.
£2,000 total
- Stone: a round or oval of about 1.0 to 1.3 carats, F–G colour, VS clarity, excellent cut. Budget £1,100 to £1,400.
- Setting: a simple hand-finished solitaire in 18ct gold or platinum, £600 to £900.
- What you get: a ring that, in mined terms, would have cost £5,000 or more. Cut is where to spend; do not chase D colour at this budget.
£5,000 total
- Stone: a 2.0 to 2.5 carat centre in E–G colour, VS1 or better, from £2,500 to £3,500. Or a 1.5 carat stone and a more ambitious mount.
- Setting: £1,500 to £2,500 buys a fully hand-made design: a hidden halo, a tapered or split band, a bezel shaped to the stone, or small matched side stones.
- What you get: this is the point at which a designer house starts to make sense. The stone is no longer most of the cost, and the mount is what people notice.
£10,000 total
- Stone: a 3 carat centre of high colour and clarity at £5,000 to £7,000, or a 2.5 carat of exceptional cut with money left over.
- Setting: £3,000 to £5,000 for a three-stone or five-stone design with matched lab-grown sides, or a centre stone flanked by fancy-coloured lab-grown accents.
- What you get: a ring that simply did not exist at this price in 2018. For context, US couples in 2025 averaged a 1.9 carat lab-grown centre on a $4,600 spend;4 £10,000 is well into statement territory.
Where the budget is best spent
Cut first. It is the one grade that decides how the stone looks from across a room, and it is the one that cheaper listings most often quietly compromise.
Colour second, up to a point. G or H reads white in yellow gold; E–F is worth paying for in platinum or white gold. D colour costs more and you will struggle to see why.
Clarity last. VS2 is clean to the naked eye. Paying for VVS or flawless in a lab-grown stone buys a line on a certificate, not a visible difference.
Then the mount. Beyond about 2 carats, the next carat is less visible than the quality of the setting it sits in. That is our view as makers; it is also the view you would expect a maker to hold, so weigh it accordingly.
What the numbers do not tell you
A price band cannot show you a grey or brown undertone in a "G" stone, a cut that leaks light, or a certificate from a laboratory grading generously. UK lab-grown sales are now around 70% of engagement rings at some retailers,5 which means a lot of stones are being bought on paper alone. Whether you buy online or from a house like ours, see the stone, or a video of it against a white background, before you commit the budget to it.