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 …
Juneau County
Goethite
Formula: FeO(OH) Orthorhombic Description: Stalactitic goethite from Montreal Mine in Iron County, Wisconsin. (Image courtesy W. S. Cordua.) Goethite is a common iron mineral. It often forms by weathering of other iron-rich minerals, thus is a …
Hematite
Formula: Fe2O3 Hexagonal Description: “Needle Ore” hematite, longest needle is about 20 cm long. From Montreal Mine in Iron County, Wisconsin. (Image courtesy W. S. Cordua.) Hematite is an extremely common mineral. It can form as a …
Muscovite
Formula: KAl2(AlSi3)O10(OH,F)2 Monoclinic Description:Muscovite is a common mica, forming silvery to pale-colored flakes most commonly schists and granite pegmatites. It can survive weathering, and form sparkling grains in sands and sandstone. Muscovite. From the mineral collection of …
Potassium Feldspar
Formula: KAlSi3O8 Monoclinic or Triclinic Description: Potassium feldspar refers to any of the three polymorphs microcline, orthoclase or sanidine. The distinction between these minerals can be made with certainty only after detailed X-Ray analysis. This has not …
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 …
Rutile
Formula: TiO2 Tetragonal Description: Rutile from the Nine Mile Pluton near Wausau in Marathon County, Wisconsin. Scanning electron microscope image. (Photo by Al Falster.) Rutile is an accessory mineral found in a wide variety of rocks, usually as …
Geologic Map of the Eastman and Harpers Ferry 7.5-Minute Quadrangles, Crawford County, Wisconsin
The geologic map of the Eastman and Harpers Ferry 7.5-minute quadrangles (Crawford County), located in the Driftless Area of southwestern Wisconsin, provides new observations and lithologic descriptions of the area’s geology. This work supports …
Geologic Map of the Ferryville and Lansing 7.5-Minute Quadrangles, Crawford County, Wisconsin
The geologic map of the Ferryville and Lansing 7.5-minute quadrangles (Crawford County), located in the Driftless Area of southwestern Wisconsin, provides new observations and lithologic descriptions of the area’s geology. This work supports the …
Geologic map of Mill Bluff State Park, Monroe and Juneau counties, Wisconsin
The Geologic Map of the Mill Bluff State Park provides a detailed look at the bedrock geology present at one of Wisconsin’s most cherished natural sites. The map and accompanying report present the Paleozoic …