Kimaï

24 Chiltern St, W1U 7QE · 07897789225

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Kimaï was founded in 2019 by Jessica and Sidney, childhood friends from Antwerp who both grew up in the diamond trade. Her family were traders; his father and grandfather were jewellers, and he holds GIA certification in diamonds and coloured stones. They then built a business selling lab-grown stones exclusively, which given the backgrounds is either ironic or well informed depending on your view.

The pitch is straightforward. A lab-grown diamond is chemically and optically the same material as a mined one, costs considerably less, and lets a given budget buy a noticeably larger or cleaner stone. Everything is set in recycled gold, and they hold B Corp certification. Rings are handmade in Antwerp.

This is the direct opposite of the Hatton Garden and Mayfair model on almost every axis: prices published online, a shop you can walk into on a Tuesday afternoon, and no pretence that the stone is rare.

You can buy from stock or commission. Existing designs are customisable on cut, carat, shape and band, which covers most people. Full bespoke runs through consultation, sketches, diamond selection with a gemologist against your budget, then making, and requires a £500 deposit that comes off the final invoice.

Production is up to six weeks for bespoke, six to eight weeks for engagement rings generally, and about ten days for ready-to-ship. Stones above 0.5ct carry an IGI, GIA or HRD certificate, and they note they mostly use IGI, with the others available on request for larger stones. Resizing is complimentary on all their engagement rings.

Read this part carefully: all rings, including engagement rings, plus anything engraved or made to order, are final sale and cannot be returned or refunded. That is a materially tighter policy than most of the trade and it applies even to stock designs.

This suits someone who has decided a lab-grown stone is the sensible choice and wants to get on with it, without a lecture about resale value. Your budget goes considerably further here than anywhere in Mayfair, and the pricing is on the website rather than extracted through an appointment.

It also suits anyone who wants to see rings without booking a private consultation first. Genuine walk-in access to engagement rings is rare in London, and worth something if you are still working out what you like.

It will not suit you if you want a natural stone, if resale or heirloom value matters to you, or if you want the reassurance of being able to return a ring you have changed your mind about. That last point is the one to weigh hardest, because the final sale policy is unusually firm.