New Almaden

The New Almaden quicksilver mine in the Capitancillas range in Santa Clara County, California, United States, is the oldest and most productive quicksilver (i.e., mercury) mine in the U.S. The site was known to the indigenous Ohlone for its cinnabar long before a Mexican settler became aware of the ores in 1820. By the time they were identified as mercury, the mine was perfectly timed to supply the California Gold Rush. The mine ran intermittently after 1927 and eventually closed. It was purchased by the county and is now part of Almaden Quicksilver County Park.HistoryCinnabar, bright red mercury ore, was used by the Ohlone people for paint. Andres Castillero, a captain in the Mexican Army, obtained a grant to the mine in 1846 but, occupied with his military duties during the Mexican War, soon sold it to Barron, Forbes Company, an English textile firm based in Tepic, Mexico. It was named "Nueva Almaden" by Alexander Forbes. Castillero's mining claim was confirmed by the Board of Commissioners that evaluated private land claims in California on January 8, 1856, but there was continued litigation in the District court, The United States vs. Andres Castillero. A claim of fraud was made on behalf of the Quicksilver Mining Company, which had acquired a competing land claim originating in an agricultural claim to the land the mine was on. On appeal to the Supreme Court of the United States the claim was found invalid in a decision rendered March 10, 1863. One of the competing land claims was Rancho Los Capitancillos.