The Oakland Museum of California, which is devoted to the art, history, and natural science of California, was been burglarized for the second time in two months on Monday, January 7, 2013. During the first robbery, the thief made off with a number of objects and pieces of gold that were on view as part of an exhibition about California’s Gold Rush. This week, a thief stole a significant gold and quartz box from the same exhibition. The box, which features elaborate decorations depicting early pioneer life, could be worth as much as $800,000.

Officials believe that the most recent break-in was pre-meditated and that the burglar pinpointed specific items to steal, making their way in and out of the museum very quickly. Security camera footage confirms that the thief worked alone. Both recent burglaries occurred on Mondays, when the Oakland Museum is closed to the public. Officials are investigating whether or not the two crimes are connected.

A $12,000 reward is being offered for the safe recovery of the box, which officials fear could be melted down for its materials.