Three masked men smashed an SUV into the front-windows of The Wells Fargo Museum in San Francisco's financial district at around 230am Tuesday, making off with 10 ounces of "historic gold nuggets." As AP reports, robbers in Northern California have targeted precious metals in museum displays before and the tactics of the heist have marked other recent robberies in the area. The men escaped in a second vehicle, according to KGO, and the vehicle reportedly headed east across the Bay Bridge. Local coin dealers said the robbers may have difficulty selling the nuggets unless they melt them down. No dollar bills, Euros, or Japanese Yen notes were stolen during the robbery. As AP reports, Thieves in a stolen SUV smashed through the glass doors of the Wells Fargo History Museum in downtown San Francisco before dawn Tuesday and made off with up to 10 ounces of historic gold nuggets worth roughly $10,000, police said. But rare coin dealer Don Kagin says the robbers may have difficulty selling the nuggets unless they melt them down. Word of the heist was spreading through the rare coin community, Kagin said, and dealers will be on the lookout for nuggets and coins with historical significance that suddenly appear on the market. The three masked thieves held a security guard at gunpoint, took around 10 ounces of gold from an exhibit case and got away in a waiting sedan, police said. The guard wasn't injured. ... With the SUV still wedged in the revolving doors Tuesday morning, people walking to work stopped to look at the aftermath of the robbery and snap pictures, while police surveyed the damage. Shattered glass crunched underneath the tires of a tow truck pulling the green 1992 Chevrolet Suburban from the building. * * *The museum is in the 400 block of Montgomery Street and houses “real gold from California gold country regions,” a Wells Fargo stagecoach from the 1860s and a working telegraph, according to the museum’s website. In addition to the stagecoach, used in the 1860s, the museum has a working telegraph and art and historical artifacts on display. * * * The men escaped in a second vehicle, according to KGO. The vehicle reportedly headed east across the Bay Bridge. * * * Not the first time... Gold nuggets also were taken in a September 2012 robbery at the California State Mining and Mineral Museum. Five men were convicted of stealing $1.3 million in gold, quartz and other valuable metals from the museum in the western foothills of the Sierra Nevada mountains. Some of the stolen items, including a bag of ground-up quartz, were recovered. But about $12,000 worth of gold was sold to pawn shops and dealers, police said. It was the second heist that year of valuable metals in Northern California. In February 2012, thieves made off with large chunks of gold on display in a Siskiyou County courthouse. * * *A New Gold Rush?