Sandstone
Around the city of Boise, there is one predominant material that has been used for buildings, foundations, and even roadway curbs. One of the oldest and most predominant uses of sandstone is to the northwest of this geocache, the historic Assay Office, a National Historic Landmark. Bring a pen/pencil.
Historic Assay Office
Designated a National Historic Landmark (NHL) in 1966 and listed in the National Register of Historic Places (NRHP) in 1980, it is one of three buildings in Idaho to be granted NHL status. The Assay Office is significant for its association with the development and professionalism of mining in the Intermountain West and for the subsequent settlement and economic development of a vast region of the nation’s interior. The building was constructed by the Federal Government in 1870-71, and, for over a decade, was the most important example of public architecture in Idaho. The Assay Office is a symbol of the importance of mining in the political, social, economic, and legal development of Idaho and the West and represents the legacy of federal encouragement of mining in the region.
The discovery of gold in California’s Sacramento Valley in 1848 sparked the first of many gold rushes that would draw countless dreamers, investors, miners, and suppliers westward over the course of the next half-century. This first gold rush was followed a decade later by the identification of the Comstock Lode in western Nevada. The next year, in 1860, gold was discovered near the Clearwater River in Washington Territory, in what would later become the Idaho Panhandle. Subsequent strikes in what is now southwestern Idaho’s Boise Basin increased the region’s notoriety in 1862. The importance of these precious metal discoveries to the history of Idaho was recognized by President Lincoln’s creation of Idaho Territory with its capital at Lewiston in March of 1863.
The ore extracted by mining operations in the newly-created Idaho Territory was rich. Between 1861 and 1866, Idaho's gold output totaled somewhere between $42 and $52 million or about 19% of the United States’ total during this period. This yield placed Idaho third--after California and Nevada--in gold production during that period.
However, despite their contribution to the nation’s economy, Idaho miners were isolated from federal services by great distances and rugged mountain terrain. While private assayers could be found locally, the nearest U. S. Department of the Treasury facilities that could provide official governmental ore reports were in Denver and San Francisco, to which travel required extraordinary effort and expense. As early as 1864, the Idaho territorial government began lobbying for a federal mint or assay office, but it wasn’t until 1869 that a federal appropriation was made for the construction of an assay office in Idaho.
The new $75,000 building would be constructed at Boise, to which the Idaho territorial government had relocated in 1866. Alexander Rossi donated all of Block 35 of the Boise City Original Townsite; a “dry plat of desert sagebrush” a few blocks east of the young town’s business center. Plans and specifications for the building were drawn up under the direction of Alfred B. Mullet, Supervising Architect of the Treasury and construction began in June of 1870. Built of rusticated local sandstone, the two-story Italianate building at the center of its block is surmounted by a low hip roof and central cupola. Decorative features of the design are limited to quoining at the corners and around the fenestration and stylized references to the Department of the Treasury in the façade’s central pediment.
Although construction was completed in July of 1871, a delay in the arrival of machinery prevented the opening of the assay office for business until the spring of 1872. Despite its modest size, the new office would have been one of the earliest monumental buildings in the Intermountain West. Its dignity, style, and substantial stone construction contrasted sharply with the prevalent log and wooden buildings in the new territorial capital, bringing the first real sense of permanence to what was in many ways largely still a boomtown supplying nearby miners. The landscaped grounds that surrounded the building were planted with trees and shrubs donated by Boise residents and acted as the first public park in the growing city.
Ironically, the opening of the Assay Office in Boise coincided with a decade-long decline in gold and silver production in Idaho Territory. However, new, rich ore discoveries led to a rush in the Coeur d’Alene region of Northern Idaho in 1883, and by the following year, gold production in the territory had doubled. The arrival of the railroads in the mid-1880s provided access to foreign and domestic capital and allowed the transport and delivery of sophisticated new machinery needed to access underground mineral veins. Deep mine shafts were sunk, stamp mills and smelters were erected, and new mines, producing silver and lead, were opened.
The expansion of the railroad across the west, coupled with the cyclical discovery and exploitation of mineral wealth, resulted in an influx of new residents to the region. The promise of untapped virgin timber and other natural resources combined to warrant governmental recognition. A quick progression of six western states joined the union in 1889 and 1890, with Idaho statehood occurring on July 3, 1890.
In 1895 deposits in the Assay Office reached more than one million dollars for the year, and over the next eleven years deposits averaged more than 1.5 million dollars annually. Idaho mines had yielded a total of $400 million in minerals by 1917: one-quarter in gold, one-quarter in silver, and one-half in lead.
A steady decline in mineral production coupled with the early 20th Century growth of timber production in the state resulted in the transfer of the Assay Office to the U.S. Forest Service in 1933. While completing substantial interior alterations upon acquisition, that agency left the building’s exterior and grounds largely intact. In August of 1972, a century after construction, the Assay Office was transferred by the Federal Government to the State of Idaho, specifically to the Idaho State Historical Society. It continues to be owned by the agency, which houses the State Historic Preservation Office (SHPO) and the Archaeological Survey of Idaho in the building.