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 …
Monroe County
Dolomite
Formula: CaMg(CO3)2 Hexagonal Description: Dolomite forms the main mineral in the bluff-forming rocks along the Mississippi River, such as Granddad Bluff near La Crosse. (Image courtesy W. S. Cordua.) Dolomite is an abundant mineral in Wisconsin. It …
Glauconite
Formula: (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2 Monoclinic Description: Glauconite is abundant in the Paleozoic sandstones in Wisconsin where it forms rounded dark green sand-sized nodules. At places glauconite may make up the majority of the rock, forming what are commonly called …
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 …
Ice
Formula: H2O Hexagonal Description: Ice is a mineral found seasonally in all parts of Wisconsin. It occurs as euhedral skeletal crystals and nodular aggregates up to baseball size precipitating from the atmosphere, accumulating on the ground …
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 …
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 …