BERLIN -- German police say a gold-and-platinum tiara adorned with 367 diamonds that once belonged to a duchess has been stolen from a state museum.

The theft of the tiara, valued at $1.31 million, from the Badisches Landesmuesum in the city of Karlsruhe was discovered on April 29, Baden-Wuerttemberg criminal police said Monday. They're now looking for any witnesses who may have seen anything out of the ordinary around that time.

The ornate tiara was stolen from a locked cabinet in the museum's throne room.

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The piece had belonged to Grand Duchess Hilda von Baden, who lived from 1864 to 1952, and dates to the beginning of the 20th century.