Blue Nile

Blue Nile carries loose diamonds across the full range of shapes, from round and princess to oval, emerald, cushion, marquise, pear and asscher, and its diamond finder lets you filter by carat, colour, clarity and cut. The stones shown are GIA certified, and both natural and lab-grown options are available. The Design Your Own path lets you begin with either a diamond or a setting, so the stone-first route is built in.

The site provides gemologist-level filtering tools and shows the standard 4C grades as you search, including colour and clarity scales and cut quality. If you’d rather talk it through, there’s a virtual appointment option alongside phone and chat support, and orders ship with secure delivery. For a Zurich buyer, the sheer size of the certified inventory makes it easy to compare a lot of stones in one place.