Thieves armed with pickaxes take $2 million in gems, gold from Calif. museum, officials say

(CBS/AP) SAN FRANCISCO - Investigators continued their search Monday for the thieves who armed themselves with pickaxes and robbed a mining museum in broad daylight, making off with an estimated $2 million in precious gems and gold.

The robbers weren't able to get away with their biggest prize- the nearly 14-pound Fricot Nugget, a giant crystalline gold mass unearthed in the Gold Rush era. As they were attempting to grab the massive nugget, the thieves triggered an alarm that alerted authorities who swarmed the museum, but were unable to nab the culprits.

At least two robbers wearing hoods and armed with pickaxes threatened workers during the heist Friday at the California Mining and Minerals Museum in Mariposa, the California Highway Patrol said.

No suspects have been identified.

The two museum employees who were onsite during the crime were not injured, but remained shaken from the experience, said the California Department of Parks and Recreation, which operates the facility.

Officials closed the museum while they repaired display cases and other items damaged by the robbers as the parks department conducted an inventory of the stolen items.

The heist was more bad news for the beleaguered museum, which is home to more than 13,000 artifacts. It was previously on a state list of facilities being considered for closure to help save money.

Authorities said the unique pieces taken would be easily identified, which could make it difficult for the robbers to sell them.

"It is uncommon for most citizens to possess such minerals," the CHP said in a statement.

This was the second heist this year of rare, valuable metals in Northern California. In February, thieves made off with large chunks of gold that were on display in a Siskiyou County courthouse.

Investigators are trying to determine if there is a connection between the two heists.