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It’s Oscar weekend, which means it’s time for a weekend of posts celebrating the only princess to have won her very own Academy Award! During her tenure as Princess of Monaco, Grace Kelly was no stranger to tiaras. One of the most unusual pieces from her own collection was this one: the Bains de Mer Tiara.

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Made by Cartier, this tiara gets its name from the company who gave it to the Monegasque princess: the Société des Bains de Mer. SBM owns some of the most important institutions in the principality, including the casino in Monte Carlo and the Hôtel de Paris, seen in two James Bond films. The government of Monaco owns 35% of SBM; the Grimaldi family owns another 35%. Not at all surprising that they’d want to offer a tiara as a wedding gift to the famous actress who was becoming their new first lady!

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The tiara itself is made of three ruby and diamond elements set on a thin diamond-studded frame. The three upright elements can be removed and worn as brooches or as pendants on a necklace. Supposedly the rubies can be swapped out for diamonds, making the piece even more adaptable. I’ve said it once, and I know I’ll say it again: if you’re not going to have a large tiara collection, you need to have one that is versatile and innovative.

In the photo above, Grace wears the brooches at the neckline of her gown. At some point, a pair of ruby and diamond earrings and a ruby and diamond ring were added to the set to make it into a small parure. Many think that Grace’s husband, Prince Rainier, was the person who supplied the extra pieces. The Grimaldis retained possession of the tiara after Grace’s untimely death in 1982, although Grace remains the only person to have been photographed wearing the piece as a tiara. Today, you’re much more likely to see her daughters, Caroline and Stéphanie, wearing the brooches in various configurations. I’m crossing my fingers that one day we’ll see the current Princess of Monaco, Charlene, wearing this particular tiara.

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But the tiara — or, to be more precise, a copy of the tiara — has made another splashy appearance in recent years. It was prominently featured in Grace of Monaco, the biopic starring Nicole Kidman as the late princess. Cartier actually made an exact reproduction of their original tiara especially for the film. But although the famous jeweler signed on to the production, the Grimaldis themselves were less invested in the project; in fact, they have publicly denounced the film, calling it “pure fiction.” (I’ve seen the film, and I have to say — it wasn’t anything to write home about!)