​229g Cox Collection Argentiferous Galena Pyrite Silver Mines MO Polished For Sale

This is a massive, 229-gram premium polished ore specimen from the historic Koch Shaft in the Silver Mines District of Madison County, Missouri. This piece features a striking, 3D-like suspension of metallic ores locked within a dense, microcrystalline quartz (chalcedony-like) hydrothermal breccia.

​Suspended in the swirly, translucent matrix are distinct cubic blocks of argentiferous (silver-bearing) galena. These silver-rich pockets are encapsulated by dark alteration rims of acanthite and sphalerite, a signature of the high-temperature cooling phases in this specific shaft. Swirling throughout the hard silica groundmass is a finely disseminated metallic gray sulfide dust, which flashes brilliantly alongside bright veins of massive pyrite and pockets of fluorite

​This piece has been professionally worked for premium display. A flat base was cleanly cut so the large, 4-inch specimen stands up with its length horizontal. The primary face has been taken to the lapidary wheel and polished to a flawless, mirror-like finish. Because the host matrix is an exceptionally hard silicified quartz breccia, it takes a glass-like polish that provides a deep, three-dimensional window into the suspended metals, while the back and sides retain their rugged, natural exterior.

​Dimensions: 5.5" x 3.375" x 1"

Weight: 229 grams

Provenance: Verified Guy Henry Cox Collection

​The History: The Koch Shaft & The Silver Mines District

This specimen is a verified piece of pioneer-era American mining history from the renowned Guy Henry Cox collection. Located along the St. Francis River, the Einstein Silver Mine district is a geological anomaly in the Midwest. Over a billion years ago, superheated, silica-rich greisen fluids shattered the Precambrian granite and diabase host rock, cementing the breccia back together with these heavy metallic ores.

​First prospected in the late 1800s for its silver and lead, the Koch Shaft later became a strategic target during the WWI mining boom. Miners drove deep into this hard rock chasing the heavy sulfide veins. Today, the entire Silver Mines district is strictly off-limits to collecting. Specimens of this size, weight, and verified historic provenance are exceedingly rare artifacts of Missouri's hard-rock legacy.

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