From the Guidebook:
This is San Francisco’s
second mint (1869). California’s only such Federal
Greek Revival structure. Due to unsurpassed productivity,
it became a sub-treasury in 1874. Intact after the 1906
disaster, it served as a clearinghouse bank, thus aiding
in the city’s reconstruction. Closed in 1937, it
was restored in 1972-1976 by Mint Director Mary Brooks.