From sparkling multi-million-dollar diamonds to custom designs, here are the most expensive diamond rings in the world that redefines luxury.

In the age of private sales and auction-house theatrics, the old metrics of diamond value—cut, clarity, carat and color—are only the opening act. True connoisseurs are chasing rarity, provenance ...

We take a closer look at the path to acquiring specimens worthy of museum display cases and generational legacy collections.