Skydiamond

Skydiamond grows diamonds from carbon captured out of the atmosphere, and it states that producing a carat this way cuts greenhouse gas emissions by 99.79 percent compared with a mined carat, a figure it attributes to an assessment by Imperial College London. The company describes itself as carbon-negative by design rather than through offsetting, and it holds GreenCode sustainability accreditation. Settings use recycled gold and platinum, and there is an online ring builder along with bespoke design.

The business is based in Stroud, in the Cotswolds, where the showroom near Stroud also lets visitors see the diamonds being created, and there is a second showroom by appointment in London. UK shipping is free, and international delivery is available, so for an order to Zurich it is worth confirming the arrangements with the team since the site leads with UK delivery.