Assay Office

Assay Office is a historic building in Boise, Idaho. It is significant for its role in the history of mining in Idaho. During the first half of the 1860s, Idaho’s gold production was the third highest in the nation. Due to the difficulty of transporting bulky, heavy ores the long distance to the nearest U.S. Mint in San Francisco, there was great demand for an assaying office in Idaho. Gold and other precious metals are not mined in a pure form. In order to place a value on an ore, the precious metal must be separated from the impurities. This is what an assay office does. In 1869, Congress appropriated $75,000 to build an assay office in Boise, Idaho. The city block site bounded by Main, First, Idaho and Second was donated by Alexander...