Wulfenite

📍Silver Bill Mine, Costello Mine Group, Gleeson, Turquoise Mining District (Courtland–Gleeson Mining District), Cochise County, Arizona, USA
Dimensions: 54/33/27mm

This specimen comes from the Silver Bill Mine in Cochise County, Arizona, part of the historic Turquoise (Courtland–Gleeson) Mining District, an area known for its colorful and storied mining past. Within the vug are several clusters of small but perfectly transparent wulfenite crystals. Though tiny, the crystal faces exhibit remarkable glassy luster and sharpness under magnification, showcasing the beauty and precision typical of the species.

The Silver Bill Mine was first discovered in 1890 and intermittently operated from 1893 to 1978, producing lead, zinc, silver, copper, gold, and tungsten. In its oxidized zones, a wide variety of attractive secondary minerals formed. The deposit occurs in Pennsylvanian–Permian Naco Group limestone, near a quartz monzonite contact zone, with mineralization controlled by faults and fractures. Intense oxidation facilitated the redeposition of malachite, azurite, and wulfenite within cavities — the very environment in which this specimen’s crystals grew.

Although the mine’s production was never extensive, it remains an important locality in Arizona’s mining history. Situated northeast of the old town of Gleeson within the Coronado National Forest, it is a classic locality. Transparent and well-preserved wulfenite crystals like these are rare from this mine, making this specimen a fine representative of the classic mineralogy of the American Southwest.