Kate wears the earrings at the Victoria and Albert Museum (Photo: Chris Jackson – WPA Pool /Getty Images)

Among the heirloom royal jewels that the Duchess of Cambridge has worn, the sapphire and diamond fringe earrings that belonged to the late Queen Mother are among my absolute favorites. The earrings somehow manage to be classic and fun all at the same time.

Photo: Chris Jackson – WPA Pool /Getty Images

The earrings feature a diamond stud with a dangle made of a large sapphire surrounded by diamonds; a delicate, almost geometric diamond and sapphire fringe is suspended from that sapphire and diamond cluster. Kate has only worn them once so far in public: for a 100 Women in Hedge Funds gala dinner held at the Victoria and Albert Museum in October 2015. Unfortunately, Kate wore them with her hair down, which means that our views of the earrings were slightly obscured. (In many photographs from the event, you can’t see them at all.)

You can see the design of the earrings a little better in the composite photo above, which shows the Queen Mother wearing them. (She’s paired them with one of my favorite brooches: the large diamond, sapphire, and gold filagree brooch from the Russian imperial collection.)

Photo: Chris Jackson – WPA Pool /Getty Images

I don’t think we know much about the earrings’ provenance beyond their association with the Queen Mother, but to me, they look like 20th century pieces. Here’s hoping we see Kate bring these out again — perhaps with her hair pulled back, so we get a clearer look at the jewels?

William, Kate, and Harry launch the Head Together campaign (Photo: Stuart C. Wilson/Getty Images)

The Duke and Duchess of Cambridge teamed up with Prince Harry on Monday to launch “Heads Together,” a campaign to raise awareness and support for mental health issues.

Photo: Jeremy Selwyn – WPA Pool/Getty Images

Kate selected one of her most-worn pairs of earrings: her diamond and sapphire cluster drop earrings. This is the pair that some have speculated were made from a pair of Princess Diana’s earrings. (That hasn’t been conclusively proved, but I think it’s a very interesting thought.)

Photo: Stuart C. Wilson/Getty Images

Here’s another look at Kate wearing the earrings. She also has a similar diamond cluster pair with emerald center stones. She often wears these earrings and their emerald counterparts for daytime engagements — they add just enough glitter, but they’re still appropriate for day.

Kate wears her borrowed diamond chandelier earrings (Photo: Kevork Djansezian/Getty Images)

As we’ve seen over the past few weeks, the Duchess of Cambridge’s jewelry box is brimming with jewels set with precious and semi-precious stones. But she’s also been loaned several pieces of jewelry by her grandmother-in-law, Queen Elizabeth II. Today’s diamond chandelier earrings are among those borrowed jewels.

Photo: Mark Large – Pool/Getty Images

Kate first wore the earrings during the Cambridges’ 2011 visit to Los Angeles. During that event, the press revealed that the earrings were on loan from the Queen, something later confirmed to royal blogger Anna by Richard Palmer of the Express. The earrings feature delicate diamonds in a chandelier design surrounding a large pear-shaped diamond.

Photo: Dominic Lipinski/AFP/Getty Images

We saw the earrings on Kate for a second time as she arrived for the 2013 diplomatic reception at Buckingham Palace, and for a third time at the state banquet held for the Chinese president in 2015. On both occasions, Kate wore them with the Lotus Flower Tiara.

Kate wore the earrings again for the diplomatic reception last December, pairing them this time with the Lover’s Knot Tiara. By now, the earrings appear to be a firm, long-term jewel loan from the Queen to Kate. To my knowledge, although the earrings belong to the Queen, we’ve never seen a photo of the Queen wearing them.