Blackacre
A bespoke house built around a single exceptional stone, run by a founder who travels to Sri Lanka and Colombia to buy them himself, and the only jeweller here with a B Corp score in the high nineties.
9 Warwick Ct, WC1R 5DJ
The most rigorous sourcing story of any jeweller on this site, backed by a B Corp score of 99.3 and a founder who buys stones in person. Ninety-six reviews without a single blemish. Go if provenance matters to you and you have £5,000 upward. Do not go looking for a quick conventional solitaire.
Bespoke and design process ×29Depth of knowledge ×19Patient with questions ×11Ring exceeded expectations ×10Kept informed throughout ×10Guided a nervous first-timer ×9
The Stone Comes First, and the Founder Goes and Gets It
Samuel Stirrat founded Blackacre in 2017, having started making jewellery at twelve and read geography at university. The name comes from the spot in Cornwall where a client couple got engaged. The proposition is narrow and clear: one exceptional natural stone, then a ring designed around it, rather than a setting you pick and a stone you slot in.
What makes that more than a slogan is where the stones come from. Stirrat travels to source them, and the site documents buying expeditions to Sri Lanka, Colombia, Kenya and Tanzania. For a coloured gemstone in particular, which has nothing like the certification infrastructure diamonds enjoy, who bought the stone and where matters considerably more than it does for a certificated brilliant.
They became a certified B Corp in 2024 with a score of 99.3, after what they describe as eighteen months of assessment. For context, 80 is the passing threshold and only a handful of jewellery businesses anywhere hold the certification. They also won Bespoke Jewellery Retailer of the Year at the 2026 UK Jewellery Awards.
Most jewellers will tell you a stone is ethically sourced. This one can tell you which valley it came out of.
London Engagement Rings#70 of 305 Verified London Jewellers
Our Top 100 ranks every London business we could verify as a genuine engagement ring jeweller, 305 of them from a pool of 1,120 candidates, on the strength of their Google review evidence. Blackacre ranks #70 of 305.
They also appear on six of our ranked lists: No. 2 on our Best Bespoke list, No. 2 on our Best Independent list and No. 5 on our Natural Diamond list, and they are on our Outside Hatton Garden, First-Time Buyers and Highest Rated lists.
The Right Buyer for Blackacre
This suits someone who wants a coloured stone, or a diamond chosen for its individual character rather than its certificate, and who finds the provenance question genuinely interesting rather than a box to tick. If you would enjoy a ninety-minute conversation about why two sapphires that look identical are priced differently, you will enjoy this.
The B Corp certification and recycled metals make it the strongest option on this site for a buyer to whom sourcing genuinely matters, as opposed to one who wants to be told it is fine.
It will not suit you if your budget is below £5,000, if you want to browse a case of finished rings, or if you need something in a fortnight. It is also not the place for a buyer who wants a conventional solitaire and does not much care where the stone came from, because you would be paying for expertise you have no use for.
First ring? Blackacre sits on our First-Time Buyers list, and our beginners guide covers budget, stones and how a first visit works.
Read it before any shop →Run Blackacre?
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Blackacre: Frequently Asked Questions
How much do Blackacre engagement rings cost?
Published designs start at £5,000, with others at £5,750, £16,000 and £18,500, and some pieces priced on application. As the rings are built around an individual stone, the stone rather than the setting drives the final figure.
How long does a Blackacre ring take to make?
Their own pages give two figures, five to six weeks on the process page and six to seven weeks on the buying advice page, both from confirmed order. Plan for six to seven. Rush requests are considered case by case.
Can I visit without an appointment?
No. They work strictly by appointment so each client gets undivided attention. The studio is at Cobham House, 9 Warwick Court, about three minutes from Chancery Lane. They ask for 24 hours notice to cancel.
Does Blackacre use lab-grown diamonds?
The work is natural diamonds and coloured gemstones throughout, and the whole proposition rests on the provenance of mined stones. They do not publish an explicit policy rejecting lab-grown, so ask directly if it matters to you.
Continue Exploring
Also on our ranked lists: Best Bespoke #2 Best Independent #2 Natural Diamond #5 Outside Hatton Garden First-Time Buyers
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