Need an opinion or expert evaluation on a piece of second-hand diamond jewellery? Meet Jonathan Weissbart — partner at S Weissbart and passionate marathon runner — the person you’ll want to speak with. Anyone who’s had the pleasure of meeting Jonathan at our London office will tell you the same thing: from the moment you sit down with him, you feel at ease, as if catching up with an old friend.

If you’ve ever visited our London office, there’s a good chance you’ve met David Weissbart. Partner owner of S Weissbart, David is a true wellspring of diamond expertise—always generous with his knowledge and happy to offer guidance to those new to the industry. Following in his father’s footsteps, he’s approachable, customer-focused and passionate about upholding the values that have shaped the business.

At S Weissbart, we believe sourcing diamonds responsibly means more than just Cut, Colour, Clarity, and Carat. As an RJC-certified, second-generation diamond dealer, we add two more Cs: Certification and Confidence. Built on trust and transparency, we’re committed to ethical sourcing and long-term client relationships—so you can trade with confidence at every step.