Formula: FeCO3 Hexagonal Description: Siderite forms as a sedimentary precipitate, in hydrothermal veins, in metamorphic rocks formed from such protoliths, and, rarely, in pegmatites. In sedimentary environments it forms in extensive beds of banded iron formations …
Iowa County
Smithsonite
Description: Massive to botryoidal smithsonite of a form originally called “dry bone ore” by miners. This was a major zinc ore in the mines of southwestern Wisconsin. From the Little Giant Mine, near Shullsburg, Lafayette …
Sphalerite
Formula: ZnS Isometric Description: Banded sphalerite, near Hazel Green in Lafayette County, Wisconsin. Sample is about 1 cm long. Sphalerite occurs in a wide range of hydrothermal environments. It is common with chalcopyrite in exhalative massive …
Sulfur
Formula: S Orthorhombic Description: Sulfur. From the Bureau of Mines, Mineral Specimens C\01732, courtesy of the U.S. Geological Survey Denver Library Photographic Collection. Sulfur forms around volcanic fumaroles, in sedimentary rocks as a result of bacterial …
Tenorite
Formula: CuO Monoclinic Description:Tenorite is a black massive mineral found in the oxidized portions of copper deposits where it is associated with other secondary minerals such as cuprite, malachite, azurite, goethite and hematite. It usually forms …
Violarite
Formula: FeNi2S4 Isometric Description:Violarite is a massive grey sulfide formed in hydrothermal deposits with other nickel minerals such as millerite.IOWA COUNTY: Violarite has been identified at several of the old zinc-lead district mines, particularly in the Linden area. …