Chlorargyrite

specimen number:
2273012

location:
Calico Mine, San Bernardino Co., California, USA

description:
An open pocket lined crystallized chlorargyrite. In good condition, this is a rare locality piece. Several previous labels come with the specimen as shown at the end of the video.

The Calico mining district, located in the Calico Mountains of San Bernardino County, California, was a highly productive precious metal and industrial mineral center exploited through an intricate system of underground tunnels, adits, and surface quarries. Geologically, the district is situated within the Mojave Desert block, where a thick sequence of Miocene-age volcanic tuffs, tuff-breccias, and lakebed sedimentary deposits belonging to the Pickhandle and Barstow Formations underwent intense faulting and folding. Hydrothermal fluids circulating along these complex regional fault lines precipitated low-sulfidation epithermal mineralization, creating silver-rich veins and disseminated deposits dominated by cerargyrite (horn silver) and native silver within a gangue of barite, jasper, and chalcedony, while adjacent lakebed strata hosted massive beds of borate minerals like colemanite. Historically, the district exploded into existence following the discovery of silver in 1881, leading to a massive boom and the establishment of major underground operations such as the Silver King, Oriental, and Garfield mines. Commercial silver extraction peaked in the late 1880s but entered a severe, permanent decline following the Silver Purchase Act repeal of 1893, though specialized borate quarrying and intermittent silver reworking continued into the early twentieth century before all large-scale commercial mining ceased by the 1910s, leaving the area to transform into a preserved historical ghost town.

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