Formula: BaSO4 Orthorhombic Description:Baryte is found general in low temperature hydrothermal deposits. It is most common in Wisconsin in the Upper Mississippi Valley zinc-lead district in Grant, Iowa, and Lafayette Counties where it is associated with …
Milwaukee County
Calcite
Formula: CaCO3 HEXAGONAL Description: Calcite sceptor crystals from Shullsburg, Wisconsin. UW–River Falls specimen. Sample is about 8 cm high. (Photo by Pete Rodewald.) Calcite is an abundant mineral found in many geological environments. It forms by precipitation from …
Celestine
Formula: SrSO4 Orthorhombic Description:Celestine forms as a groundwater or low temperature hydrothermal precipitate in sedimentary rocks such as limestones and dolostones.IRON COUNTY: Dickey (1938) describes celestine as occurring in small bluish crystals up to 0.3 mm long …
Honessite
Formula: Ni6Fe2(SO4)(OH)16.4H2O Hexagonal Description: Honessite is one of a number of secondary nickel sulphates formed by the weathering of primary hydrothermal nickel sulfides such as millerite, violarite or nickeliferous pyrite (so-called “Bravoite”). It is found at …
Hydrocarbons
Formula: Mixtures Description: Solid hydrocarbons, generally unanalyzed in detail, are found at a number of localities within the Paleozoic rocks around the state. They may be alternately described as “bitumen” or “asphaltum”. These usually occur as …
Marcasite
Formula: FeS2 Orthorhombic Description: Marcasite helectite, New Diggings area, Lafayette County, Wisconsin. Sample is about 8 cm long. (Photo by W. Cordua.) Marcasite is common in Wisconsin, often found in well-formed crystals in cavities and veins in the …
Millerite
Formula: NiS Hexagonal Description: Millerite is a low temperature hydrothermal mineral found in vugs in carbonate rocks and as an alteration product of other nickel minerals. Millerite typically forms long brassy fibers making very aesthetic specimens. …
Pyrite
Pyrite is the most common sulfide found in many environments. It is a common accessory mineral in igneous, sedimentary and metamorphic rocks. It also is abundant in most hydrothermal deposits. Only the most significant occurrences …
Quartz
Formula: SiO2 Hexagonal Description: Quartz is the most abundant mineral. It is an essential component of granitic igneous rocks, of sedimentary rocks such as sandstone and chert and of metamorphic rocks such as quartzites. It is a …
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 …