Graff

Graff is the name at the very top of the London diamond market — and it started on Hatton Garden. Laurence Graff opened his first shops on the street in the early 1960s before moving to Bond Street. Today the London flagship is at 6-8 New Bond Street, with a second store on Sloane Street and a Harrods concession.

The engagement range is built around house designs: Promise, Icon, Paragon, Legacy, Flame, Constellation and the Laurence Graff Signature collection. You choose a design, then a centre stone is matched to it. Graff's UK site lists the Paragon solitaire from £3,700, and Promise and Icon rings run well into five figures. Larger stones are price on request.

Graff says its diamonds are GIA-certified and graded on the 4Cs, then adds a fifth quality it calls "character" — the house's own judgement of how a stone looks. That's worth understanding. The GIA certificate is the part you can compare like-for-like anywhere. The "character" is the part you're trusting Graff's eye for.

Natural diamonds only. There is no lab-grown option, and the house leans heavily on responsible sourcing under the Kimberley Process.

Our view: you're paying a large premium for the name, the house design and the experience. If the Graff box is part of what makes the ring meaningful, that's a legitimate reason to buy here. If it's the diamond you care about, take the GIA grades from a Graff quote to Hatton Garden and see what the same stone costs there. Book ahead — walk-ins are possible, but every page of the Graff site steers you to an appointment.