The world's "biggest jewelry heist" overnight at a German museum has missed the prized Dresden Green Diamond and other signature treasures that are currently on loan to the Metropolitan Museum of Art in New York for the exhibition Making Marvels: Science and Splendor at the Courts of Europe.

A fire broke out in Dresden early Monday morning knocking out power to the Royal Palace's Grüne Gewölbe (Green Vault) collection that houses 3,000 gems and historic artifacts. While the area went dark and the museum's alarms were disabled in the power outage, thieves broke in and targeted a display case in the Grüne Gewölbe’s Jewel Room. They entered the museum through a ground floor window.

Within five minutes, video surveillance shows that two male thieves took off with numerous pieces including three “priceless” sets of brilliant-cut diamonds from an 18th-century collection of jewelry assembled by the museum’s founder. Each set consists of 37 pieces, including diamonds, rubies, emeralds, and sapphires.

In terms of value, the director of Dresden’s state art collections, Marion Ackermann, said, “We cannot give a value because it is impossible to sell.” Adding, that she hopes the jewelry will not be broken into pieces for resale since “the material value doesn’t reflect the historic meaning.”

Some experts have placed the value on the lost items at one billion euros ($1.1 billion), noting that if the pieces were broken apart and melted down, the return would still be in the hundreds of thousands of euros.

The thieves possibly had cover of darkness while speeding off on the nearby autobahn where a burning car was later found. Police were on the scene at the museum in under five minutes and also set up roadblocks.

Visitors are strictly limited and require advance reservations to access the historic Green Vault. Numerous chambers comprise an ivory room, a silver gilt room and the central Hall of Treasures.  

Michael Kretschmer, the leader of Saxony in which Dresden is the capital, decried the loss. “Not only the gallery has been robbed, but also the Saxonians,” he said. “You cannot understand the history of our country, or the free state of Saxony, without the Grüne Gewölbe and the state art collections of Saxony.”

Since 1724, the Grüne Gewölbe (Green Vault) has been a popular tourist attraction. During the devastating bombing of Dresden by British and American forces in World War II, the building sustained heavy damage. A 2006 renovation reopened the palace's Green Vault as an international destination for dazzling cultural treasures.