BERLIN (AP) — German authorities are offering a 500,000-euro ($550,000) reward for information leading to the recovery of 18th century jewels snatched from a unique collection in Dresden or the arrest of the thieves.

A large diamond brooch, a diamond epaulette and other treasures were taken from Dresden’s Green Vault early Monday morning.

Police and prosecutors said in a joint statement Thursday that “we will leave no stone unturned to solve this case.”

A 40-member investigating commission is working on the robbery.

The Green Vault is one of the world’s oldest museums. It was established in 1723 and contains the treasury of Augustus the Strong of Saxony, comprising around 4,000 objects of gold, precious stones and other materials.