Police in Yreka, Calif. are still searching for answers today after thieves stole $3 million worth of historical golden nuggets from a courthouse.

The stolen gold collection items date back some 100 years and are historic artifacts from the booming gold rush that took place here in this Northern California "golden city," so nicknamed for its major role in the rush.

Police believe the thieves broke into the Siskiyou County courthouse through an open window at around 1 a.m. Wednesday morning, according to Allison Giannini, the county spokeswoman.

The break-in was not discovered until the police came to work at 7 a.m. Wednesday and saw a broken display case and discovered the gold was missing.  An alarm on the case failed to sound during the burglary, Giannini said.

"We are working vigorously," she said. "We want our gold back."

The missing gold was a compilation of nuggets from every mine in the county. All of the pieces were donated by minors or relatives of minors. The only purchased item in the collection was a 28 ounce piece of gold resembling a shoe. It was bought in 1913 for about $550 dollars.

Wayne Hammar, the Siskiyou County treasurer and tax collector,  said that while the monetary value of the gold is substantial, what matters more is the loss of the county's heritage.

Roughly 740 ounces of gold were stolen from the case.  "They are specimen-quality pieces," he said. "It is our history, these folks have taken a big part of our history. "

The county is located near the Oregon border and was founded to serve the gold mining industry. It was a key location for the historic West Coast Gold Rush. Despite the large monetary value of the items, Giannini says loosing this part of their history is devastating.

"You can't put a value on our history. It is invaluable to us really," Giannini told ABC News. "It is irreplaceable."