Thanks to the likes of Taylor Swift and Lauren Sánchez, the engagement ring game has become something of a competitive sport.

The largest cut diamond known to exist, weighing 555.55 carats, sold for £3.2 million (US$4.3 million) at a Sotheby’s single-lot online sale that closed Wednesday. The black diamond was offered from ...

Learn all about the old mine cut diamond, the stone found on Taylor Swift’s engagement ring from Travis Kelce.