A one carat lab grown diamond engagement ring starts at £706 at Luma today. That is the Clio bezel solitaire in 9k gold at £540, with a one carat IGI certified round brilliant in the D to F colour range and VVS2 clarity priced on top. We price the setting and the stone as two separate figures rather than one blended number, so you can see exactly what each part costs and move your budget between them. A heavier metal, a setting with accent diamonds or a larger or cleaner stone all raise the total from there, and we show you every figure before you order. The same one carat specification in a mined diamond would cost many times more, which is the whole reason this number looks the way it does. Every ring is made to order in our Hatton Garden workshop and hallmarked in the UK.
Written by Asher Wiener, co-founder of Luma Jewellery, from our Hatton Garden workshop. Last updated 22 September 2026. Setting prices on this page match our live prices today, and we price each diamond live at the moment you choose it, so the total moves with the stone you pick.
Settings for a one carat diamond
ClioBezel solitaireSetting from £540
AnoukClassic solitaireSetting from £530
AmaraHaloSetting from £680
CosetteTrilogySetting from £830
Each price is for the setting. Every one of our settings holds a stone from 0.5ct to 3.0ct, and we price your certified diamond live when you select it. See all engagement rings.
Why does a one carat lab grown diamond cost so much less than a mined one?
Because the stone is the same and the supply chain is not.
A lab grown diamond has the same carbon crystal structure, the same hardness of 10 on the Mohs scale and the same optical behaviour as a mined diamond. The gem laboratories grade both against the same standards. What a mined stone carries on top is the cost of finding it, extracting it and moving it through a long chain of hands, each taking a margin. A lab grown stone skips all of that.
There is a second thing happening, and it is worth understanding before you buy. Lab grown diamond prices have fallen a long way as growing capacity has increased, and they have fallen furthest at the sizes people actually buy. At one carat the material cost is now a small part of what you pay. Most of the price of any one carat ring today is the metal, the workmanship and the certificate.
What drives the price of a one carat lab grown diamond?
Four things, and they do not matter equally.
Cut matters most and is the one people underweight. A well cut stone returns light to the eye and looks brighter than a larger, duller one. It is also the only one of the four you cannot correct later.
Colour runs from D, which is colourless, down through the alphabet. We work in the D to F range, which reads white against any metal.
Clarity describes inclusions. We work from FL to VVS2, which are eye clean, meaning nothing is visible without magnification. Clarity matters more in a step cut like an emerald, where the open facets show everything, and less in a round brilliant where the faceting hides a great deal.
Carat is the weight. It is the number everyone quotes and it tells you least about how a ring actually looks.
How big does a one carat diamond look on the hand?
A one carat round brilliant measures roughly 6.4mm across the top. On most hands it reads as a clear, unmistakable engagement ring without being the first thing anyone notices from across a room.
Shape changes the impression more than weight does. An elongated shape like an oval or a pear spreads more of the stone face up across the finger, so a one carat oval looks larger than a one carat round even though they weigh the same. If apparent size is what you are after, changing the shape is cheaper than buying more carats.
Should you buy one carat or go larger?
This is the question worth asking, because at our pricing the answer is not obvious.
Two carats sits inside a thousand pounds here in a 9k gold solitaire, and three carats sits inside two and a half thousand. So the choice between one carat and two is rarely about affordability. It is about what she would actually wear. A two carat stone is a considerable presence on a smaller hand and some people would far rather have a one carat at a higher grade in a heavier metal.
Our honest advice is to choose the size that suits the hand and the person, then spend whatever is left on cut quality. A beautifully cut one carat outlives a badly cut two carat in every way that matters day to day.
Where can you buy a one carat lab grown diamond ring in the UK?
Buy from a workshop rather than a showroom floor. A high street chain carries rent, held stock and a retail margin on every ring, and at one carat that margin can exceed the cost of the stone itself.
We make every ring to order in our Hatton Garden workshop, set only IGI certified lab grown stones, hallmark in the UK and show the setting price and the diamond price separately so you can check each one. Price your ring online, or book a consultation in London and compare one carat stones side by side before you commit.
Common questions
How much is a 1 carat lab grown diamond ring in the UK?
At Luma a one carat lab grown diamond engagement ring starts at £706, which is our Clio bezel solitaire in 9k gold at £540 plus a one carat IGI certified stone in the D to F colour range at VVS2 clarity. Moving to 14k or 18k gold, platinum, or a setting with accent diamonds raises the total. We price each stone live at the moment you choose it, so you see the setting, the diamond and the total together before you order.
Is a 1 carat lab grown diamond worth buying?
If you want a ring to wear, yes. It is a real diamond, indistinguishable by eye from a mined stone and certified to the same standards, at a fraction of the price. If you want an asset, no. Lab grown diamonds have very little resale market, so buy one for what it is rather than what it might be worth later.
How big is a 1 carat lab grown diamond?
A one carat round brilliant is roughly 6.4mm across the top. Elongated shapes such as oval, pear and marquise look larger at the same weight because more of the stone sits face up across the finger.
Is a 1 carat lab grown diamond real?
Yes. It is chemically, physically and optically a diamond, with the same carbon crystal structure and the same hardness as a mined stone. Telling the two apart requires specialist equipment that reads the growth pattern. Every stone we set arrives with an IGI report confirming it was grown in a laboratory.
Is it cheaper to buy a 1 carat lab grown diamond ring in Hatton Garden?
Usually, if you buy from a workshop rather than a showroom. We make to order and sell direct, so you pay for the diamond, the metal and the workmanship rather than for a shop floor. The saving tends to show up in the size or grade of stone your budget reaches.
Does the price on the ring page include the diamond?
No. The figure on each ring page covers the setting only. You choose your certified lab grown diamond at step three of the builder and we price it there, because the cost depends entirely on the carat, colour and clarity you pick.
See the full range on our engagement rings collection, or book a consultation at our Hatton Garden workshop and we will build to your budget.
Related reading: lab grown engagement rings under £1,000, how much a lab grown engagement ring costs in the UK and how our pricing works.