Grace wears her diamond tiara for a gala performance in Paris, April 1967 (Keystone/Hulton Archive/Getty Images)

Today’s spotlight sparkler belonged to an American actress who married a prince — no, not that one! This classic diamond tiara resided in the jewelry box of Princess Grace of Monaco.

Grace wears her diamond tiara for the Bal de Petit Lits Blancs in Monaco, July 1966 (Keystone Pictures USA/Zuma Press/Alamy)

Although Princess Grace wore a number of tiaras during her lifetime, many of them were likely loans. The two most prominent sparklers in her own jewelry box were the convertible diamond and ruby tiara given to her by the Société des Bains de Mer, and today’s tiara, which the family apparently refers to simply as her “diamond tiara.”

Grace wears her diamond tiara for a gala performance in Paris, April 1967 (Keystone/Hulton Archive/Getty Images)

The name advertises the piece well. Although I don’t believe the name of the tiara’s maker has ever been released, various museum exhibitions have given us a clear picture of the sheer wattage of the thing. The sparkler may be small, but it has more than two hundred diamonds in its platinum setting: 214 “modern-cut diamonds” and 42 diamond baguettes. The gems are set in elements that resemble swags or festoons.

Grace wears the tiara during the 1961 state visit to Ireland

Grace began wearing this tiara in the early years of her marriage, and she selected it for some significant events, including a state visit to Ireland in 1961.

Caroline wears a tiara, possibly her mother’s diamond tiara, as she dances at the ball held before her wedding to Philippe Junot in 1978

Some also believe that this is the tiara worn by Princess Caroline to the ball held before her wedding to Philippe Junot, and I tend to agree, though the photographs and videos of the event aren’t particularly clear.

Grace wears her diamond tiara (and the ruby and diamond clips from the Bains de Mer Tiara) as she dances with the Aga Khan at the Bal de Petit Lits Blancs in Monaco, July 1966 (Pictorial Press Ltd/Alamy)

The tiara is still a part of the princely collection in Monaco, and I can’t figure out why none of the princesses have taken it out for a spin lately. Maybe the Grimaldi women are wary of donning pieces that have such strong associations with Princess Grace? (Or maybe Caroline hasn’t wanted to wear a piece with clear associations to a previous wedding again?) Whatever the case, I’m hopeful that we’ll see this one again on another member of the family — perhaps Princess Charlene or (in quite a few years) Princess Gabriella?