Tetradymite
specimen number:
2262307
location:
Boulder Co., Colorado, USA
description: The Boulder County mining district, situated in the Front Range of north-central Colorado, was a highly significant and mineralogically unique producer of gold, silver, tungsten, and fluorspar. Geologically, the area is defined by the northeast-trending Colorado Mineral Belt, where Late Cretaceous to Paleogene-age monzonite and granodiorite porphyry stocks intruded ancient Proterozoic-age granites and gneisses. This intense igneous activity generated complex epithermal and mesothermal vein systems, famously producing rich zones of gold-telluride minerals (such as sylvanite and calaverite) in the mountains around Gold Hill and Jamestown, alongside massive deposits of ferberite (iron wolframite) in the Nederland tungsten belt and high-grade fluorspar replacement bodies. Historically, the district exploded into prominence following the January 1859 discovery of placer gold at Gold Run, marking one of the earliest major strikes of the Colorado Gold Rush and leading to rapid surface quarrying and underground shaft development. Industrial corporate operations expanded rapidly over the next century, with the district shifting focus to extract massive amounts of tungsten to harden military steel during World War I and World War II, and producing metallurgical fluorspar until changing global market economics, rising deep-pumping costs, and environmental regulations caused a steady decline. While large-scale commercial corporate extraction of base and precious metals progressively wound down after the 1950s and reached general cessation by the early 1980s, the historic district has seen intermittent small-scale artisanal mining, environmental remediation projects, and localized specimen recovery efforts continuing through 2026. The Foote Mineral Company began its corporate history as an elite mineral supply house and scientific dealership established in Philadelphia, Pennsylvania, by Dr. Albert E. Foote in 1876. Strategically launching his enterprise at the Centennial Exposition held in Philadelphia that same year, Dr. Foote exhibited an extensive collection of mineralogical specimens that drew widespread acclaim from global institutions and private enthusiasts alike. Operating from prominent retail and mail-order facilities on Arch Street and later Forty-First Street, the firm specialized in compiling, categorizing, and selling systematically organized mineral sets, rare geological specimens, and scientific literature to universities, museums, and serious collectors across North America and Europe. This early business model relied on aggressive field collecting trips and a vast network of international agents to secure high-quality mineral inventory, which was meticulously processed and distributed through descriptive sales catalogs published regularly by the company. This specialized commercial endeavor established Philadelphia as a major hub for scientific mineralogy during the late nineteenth century, providing the financial foundation and corporate infrastructure that allowed the firm to successfully transition from an artisanal specimen supplier into a heavy industrial chemical and mining conglomerate by the early 1900s.
Lustrous metallic masses across matrix. The specimen has an old label glued to the backside of it from the A. E. Foote Company.
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