The second thing you need to know about the ring is that it has a long history of controversy in the royal family, dating back to when Diana picked it out. The story starts in 1981, when Prince Charles presented Diana with a selection of rings to choose from for her engagement ring, according to Vogue. The rings came courtesy of Garrard, who was the crown jeweler at the time.
Diana selected the Ceylon sapphire stone set in white gold that has since become iconic. Here’s where the controversy comes in—the ring was a stock item. Meaning? It wasn’t bespoke and any old commoner with enough money could buy exactly the same ring. Oh, the horror, right?
Clearly, Diana didn’t care about this one bit. She loved the ring and continued to wear it after her divorce from Charles in 1996.
Kate, for her part, was also thrilled to be wearing the controversial bauble. "It’s beautiful – I hope I look after it! It’s very special", she said at the time.
This article originally appeared on Marie Claire.