There is no Rapaport-style price list for lab-grown diamonds, so any UK price guide is a reading of what retailers publish and what wholesale data says underneath it. Here is that reading for 2026, with the caveat that the numbers move every quarter and only in one direction.
Published UK retail prices
Two UK retailers publish price tables rather than making you enquire, which makes them useful as evidence. They are cited here as examples of public pricing, not as recommendations.
Loose stones. Queensmith's price guide, last updated August 2025, lists D-colour, VS1, excellent-cut round lab-grown diamonds at £380 for 0.30ct, £690 for 0.50ct, £950 for 0.70ct and £1,410 for 1.00ct, rising to £1,640 at 1.20ct 1. Those are top-colour stones; an F or G of the same clarity would sit below them.
Finished rings. Lester & Brown's February 2026 guide, for GIA or IGI reported, excellent-cut stones in F–G colour and VS1–VS2 clarity, gives a one-carat round solitaire at £1,200 to £1,800 in 18ct gold and £1,400 to £2,000 in platinum; 1.5ct at £2,000 to £3,200 in gold; 2ct at £3,000 to £4,800 in gold; 2.5ct at £4,200 to £6,400. Halos and diamond shoulders add £200 to £1,000 2.
Taken together, the UK price band in 2026 looks like this:
| Stone (round, excellent cut, F–G, VS) | Loose stone, approx. | Solitaire ring, approx. |
|---|---|---|
| 0.50ct | £400–£700 | £900–£1,300 |
| 1.00ct | £700–£1,400 | £1,200–£2,000 |
| 1.50ct | £1,200–£2,200 | £2,000–£3,600 |
| 2.00ct | £1,800–£3,500 | £3,000–£5,200 |
The ranges are wide because the market is. The lower figures are large online retailers; the upper figures are Hatton Garden and designer houses, whose price includes design, making and aftercare rather than just the stone.
What sits underneath: wholesale
The reason retail prices are falling is that wholesale prices have collapsed. JCK, citing Paul Zimnisky, reports a 3-carat D VVS round wholesaling at US$126 per carat in the first quarter of 2026, down 14 per cent year on year; second-quarter prices were down a further 13 per cent; 2025 as a whole was down 26 per cent; and since 2018 wholesale lab-grown prices have fallen about 96 per cent 3. Zimnisky's 2026 analysis puts retail mark-ups at more than 80 per cent above wholesale, barely changed from 2025, and he is quoted saying current retail levels "are too high" and are supported partly by novelty "which will not last forever" 3.
US direct-to-consumer pricing, which the UK tends to follow with a lag, puts a one-carat F VS2 IGI stone at roughly US$700 to US$1,100 retail in 2026, falling per carat as weight rises 4.
The honest part
Three things follow from this, and a UK buyer should hear them before spending:
- Prices keep falling. Insurance Times reported in March 2024 that a three-carat lab-grown stone valued at £16,500 in 2021 was worth £7,500 by 2023 5. That trend has continued. Whatever you pay in 2026, the same stone will be cheaper in 2027.
- Retail margins are the cushion. Because retailers have held their mark-ups while wholesale fell, there is room for retail prices to drop faster than they have. Do not assume a quoted price is close to cost.
- Grading is getting thinner. GIA stopped issuing colour and clarity grades for lab-grown diamonds from October 2025, saying most lab-grown stones fall in a very narrow quality range 6. The IGI vs GIA page explains what to ask for instead.
How to use these numbers
Price a lab-grown diamond by what you are buying, which is a piece of jewellery. The stone is now a minor part of the cost of a well-made ring; the design, the metal, the setting and the maker's time are the rest, and those are what you still own in ten years. The resale page explains why the loose stone has almost no secondary value. The colour and clarity page explains how to spend the saving well.
If you want a specification to take to a jeweller, the Brief Builder on this page turns shape, carat, colour and budget into a one-page spec you can compare quotes against.