JCO London

Suite 47, 4th Floor, 88-90 Hatton Garden, EC1N 8PN · View on Google Maps · Visit website

JCO London is a third-generation family business. It began with the family’s grandfather and came to the UK with the next generation, and today it works from Suite 47 on the fourth floor of 88-90 Hatton Garden, with all manufacturing done in-house. Its online collections trade as JCO Diamonds.

Google shows 332 reviews. We analysed 330: 326 are five star, one is three star and three are one star. The record runs back almost ten years, with 44 reviews in the past twelve months.

Diamond selection is the most discussed topic after the engagement ring itself, ahead of wedding bands, which marks this out as a stone-led shop. Their diamonds are certified, natural and lab-grown are both on offer, and what they sell comes with a lifetime warranty and free resizing.

Our Top 100 ranks every London business we could verify as a genuine engagement ring jeweller, 311 of them from a pool of 1,120 candidates, on the strength of their Google review evidence. JCO London ranks #54 of 311.

They also appear on two of our ranked lists: Open Sunday and Lab-Grown Specialists.

Twenty-seven reviewers mention depth of knowledge, 23 describe the bespoke and design process, and 18 each mention patience with questions and aftercare or resizing. Fifteen say the ring exceeded expectations and 14 report that the partner loves it.

Four reviews are critical, and three of those are about communication: slow replies, or follow-up after a first visit that did not arrive. Against 326 five-star reviews that is a small share. Agree the next step and the timeline before you leave.

Review figures taken from Google and checked in August 2026. We recount them monthly.

This suits a buyer who wants the diamond chosen with care. Diamond selection comes up in 73 reviews, more than wedding bands, and the making happens in their own workshop once the stone is settled.

It also suits a Sunday shopper. They open Sunday 11am to 3.30pm and are on our Open Sunday list, but they close on Fridays, so plan around that.

They work from a fourth-floor suite rather than a shopfront, so book ahead. Consultations are free.

Is JCO London the same as JCO Diamonds?

Yes. JCO Diamonds is a subsidiary of JCO London and carries its online collections. The showroom is Suite 47, 88-90 Hatton Garden.

What are JCO London’s opening hours?

Monday to Thursday 10.30am to 5.30pm, Saturday 10.30am to 5.30pm and Sunday 11am to 3.30pm. They are closed on Fridays.

Do they sell lab-grown diamonds?

Yes, alongside natural diamonds, and they are on our Lab-Grown Specialists list. Their diamonds are certified.

Why are they ranked #54 of 311?

The ranking is built on Google review evidence across every London jeweller we could verify as a genuine engagement ring business. Their record is 330 analysed reviews, 326 of them five star, over almost ten years.