Mining operations in New Almaden first began in 1845 under the claim of Mexican Cavalry Officer Captain Andres Castillero. Castillero discovered that the red rock used by the local Ohlone people to paint the walls of the Santa Clara Mission was cinnabar, an ore containing mercury. The valuable mercury was needed to process silver in Mexican silver mines.
Henry Halleck, who led the management of the mines under the direction of early mine owners Baron and Forbes, had the Casa Grande ("the big house") designed and built by architect Francis Meyers in 1854. The six-acre grounds were later landscaped by John McLaren, designer of San Francisco’s Golden Gate Park. For decades, this classic revival-style mansion served as the official residence and office for a succession of mine superintendents, and as a country weekend retreat for wealthy mine investors.
The Casa Grande once boasted 27 rooms. The basement consisted of the kitchen, dumbwaiter, servant quarters, food storage, and a large vault for depositing liquid mercury, also called "quicksilver." After the closing of mine operations, the Casa Grande had a succession of private owners and served a number of purposes, including a tourist resort and recreational facility known as Club Almaden.
In 1973, the Santa Clara County Parks & Recreation Department began purchasing the old mine properties. In 1985, the Department purchased a private collection of mining artifacts from Constance Perham, a resident of New Almaden. From 1949 to 1983, Mrs. Perham had displayed mining artifacts, memorabilia, and photographs in her private "museum" in the historic village. The Parks Department leased the museum site from 1983 to 1998, and the New Almaden Quicksilver County Park Association volunteers maintained the collection and exhibits, as well as provided tours about the history of New Almaden and the Quicksilver Mines.
In 1997, the Casa Grande once again was offered for sale, and the County Parks Department seized the opportunity to add the National Historic Site to Almaden Quicksilver County Park. The existing museum collection moved to the Casa Grande, where park staff and volunteers erected a new exhibit space. The new museum opened on July 3, 1998. After an extensive building renovation from 2009 to 2010, the newly expanded museum once again opened in January 2011.
For additional information about Almaden Quicksilver Park, go to the Almaden Quicksilver County Park webpage.
Online Historical Collections
Be sure to check our online historical collections to see photos, documents, and artifacts from the New Almaden Quicksilver Mining Museum. You can also view artifacts from Martial Cottle County Park or Joseph D. Grant County Park and can request images from us.
Mercury Minutes Video Series
Mercury Minutes is a seven part video series that explores New Almaden's mining history. Episodes explain how mercury is used to process gold, the communities who mined cinnabar and processed mercury, how Santa Clara County Parks cleaned up the toxic legacy mercury left behind, and how Almaden Quicksilver County Park welcomes visitors to learn about the past while exploring park trails.