Sphalerite with Pyrite

Unknown Owner

An interesting locality example for the species, crystallized black sphalerite covering one side of matrix with crystalline golden pyrite. In good condition.The Browns Bottoms Quarry near East Dubuque, Illinois, is a limestone quarry located along the Mississippi River in an area historically associated with lead and zinc mineralization. Although primarily operated as a surface quarry for crushed stone, the site lies within the Upper Mississippi Valley region, where sphalerite and other sulfide minerals are known to occur. Specimens of sphalerite from the quarry are considered minor but representative of the regional geology, typically occurring in association with carbonate host rock. While not a major source of collectible minerals, the locality is of interest to collectors for its connection to the broader mineralized district and occasional occurrences of zinc minerals such as sphalerite.