Microcline with Quartz

specimen number:
2262302

location:
Pike's Peak region, Colorado, USA

description:
Bluish green blocky crystals of microcline, this is the variety known as amazonite, measuring to 2.2 cm in size across the top of a granite matrix with crystals of smoky quartz. Damage is present as seen. This is an old time specimen, there is a previous label from the Foote Mineral Company glued to the backside of the piece as seen in the video.

The Pikes Peak pegmatite district, encompassing portions of El Paso, Teller, and Park counties in central Colorado, is a world-famous mineral-producing region exploited through localized surface quarrying, trenching, and small-scale underground operations. Geologically, these deposits are hosted within the massive Pikes Peak batholith, a Precambrian-age granitic intrusion where late-stage, volatile-rich magmatic fluids cooled slowly to form complex pegmatite bodies and open pockets. These specialized miarolitic cavities allowed for the unrestricted growth of spectacular, large crystals, most notably the prized combination of deep green to blue-green amazonite (a lead-bearing variety of microcline feldspar) blocky crystals intergrown with contrasting dark smoky quartz crystals. Historically, formalized mining and surface quarrying for these specific pocket minerals began in the 1870s following geological surveys that brought the region's unique mineralogy to international attention. Systematic extraction was carried out by independent miners and specialized companies through the late nineteenth and twentieth centuries, with famous localities like Crystal Peak and the Lake George area producing thousands of specimens. Because these pegmatites occur as isolated, erratic pockets rather than continuous ore veins, large-scale industrial underground mining was never viable, but targeted seasonal surface quarrying and artisanal trenching operations have remained continuously active across the region through 2026.

The Foote Mineral Company, founded and long headquartered in Philadelphia, Pennsylvania, began its corporate history as the world's premier commercial supplier of mineral specimens for museums, universities, and private collectors. Geologically, the enterprise relied on a vast international network to acquire rare, well-crystallized, and scientifically significant specimens representing global mineral localities, which were shipped to Philadelphia to be cleaned, cataloged, and systematically classified according to chemical and physical properties. Historically, the business was established in Philadelphia in 1876 by Dr. Albert E. Foote following his highly successful mineral exhibit at the Centennial Exposition, quickly expanding into a massive mail-order and storefront operation that published influential mineral catalogs and shipped tons of specimens worldwide. The company's dedicated focus on the specimen trade flourished from 1876 through the early decades of the twentieth century, providing foundational collection material for major repositories like the United States National Museum and the American Museum of Natural History. As industrial demands for rare elements intensified prior to World War I, the company systematically shifted its focus from educational and aesthetic mineral specimens to large-scale industrial chemical manufacturing and ore refining, phasing out its famous specimen department by the 1920s to pave the way for its later history as a major global lithium producer.

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