Marcasite

Blackstone Mine, 

Upper Mississippi Valley Dist.,

Lafayette Co., Wisconsin,

USA

8x8x10cm

Marcasite is an iron sulfide mineral prized by collectors for its metallic luster and distinctive pale brass-yellow color. This specimen originates from the renowned Blackstone Mine in Wisconsin's Upper Mississippi Valley District, a classic locality celebrated for high-quality marcasite crystals. The cubic and pyritohedral forms typical of this deposit display sharp definition and bright surfaces. At 8×8×10 cm, this is a substantial display piece suitable for serious mineral collections. Marcasite is notably more reactive than its polymorph pyrite, making proper storage and handling important for long-term preservation. A fine example of American mineral heritage from one of the region's most productive historical sources.