ALERTPlease note: the museum will be closed on Sunday, Feb 2 for a private event. The next Target First Free Sunday will take place on Feb 9.

Thank you

The California Connection

Gold has played a key role in California’s history, with particular influence in the Bay Area. In homage to the state’s mining legacy, on display in this exhibition are two California-sourced objects that showcase gold as it occurs naturally: a quartz matrix and a placer nugget. 
Quartz Matrix
Hot, salty water deep within the earth’s crust contains dissolved gold ions. Under pressure, this gold-bearing liquid oozes upwards through any available fractures in the surrounding rock. As the gold-infused water rises toward the earth’s surface, the heat and pressure lessen. Under these conditions, the gold is no longer soluble, and it begins to crystallize out, typically surrounded by large masses of white quartz. When tectonic forces then bring gold-bearing quartz veins to the surface, weathering breaks down the matrix. Tougher gold particles are washed downstream, where their weight makes them fall out of suspension, sometimes accumulating into large nuggets called “placers.”  

Placer Nugget
When mineral veins containing gold erode, some of the metal is washed into watercourses, where its weight makes it sink. If there is sufficient accumulation of gold in a specific location, a gold nugget like the one on display in the exhibition is formed. Such nuggets are technically known as “placer nuggets,” a term that derives from the Spanish term placer (alluvial sand), in reference to the deposits in which such nuggets are typically found. Placer mining involves the famous technique of panning for gold in mountain streams, the main method used in the early years of the California gold rush.

Immigrant Miners
The promise of gold has exerted an almost magnetic pull not merely across North America, but also across the Pacific to Asia and especially China. Indeed, Chinese immigrants to Gold Rush-era San Francisco called the city “Gold Mountain.”   You can explore the role of Chinese immigrants in the Gold Rush in the exhibition Extracted, an installation of contemporary artwork by Ranu Mukherjee, which includes an innovative hybrid film along with pieces from the museum’s collection, in Gallery 18 on the second floor.