Formula: Ca5(PO4)3(F,Cl,OH) Hexagonal Description:Apatite denotes a family of minerals referred to variously in older literature as “fluorapatite,” “chlorapatite,” “carbonate-apatite” or “hydroxlyapatite” and in newer literature as apatite- (CaF) etc. depending on which anion group dominates. Members …
Grant County
Baryte
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 …
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 …
Calcite Speleothems
Formula: CaCO3 HEXAGONAL Description: Speleothems are precipitates, usually made of calcite, in caverns. They should be conserved and not be collected from caves in order to preserve the caves’ beauty, interest and scientific values. CRAWFORD COUNTY: Abundant speleothems …
Celadonite
Formula: K(Mg,Fe)(Fe3+(Si4O10)(OH)2 Monoclinic Description: Celadonite is an earthy green to blue-green mineral formed by low grade hydrothermal of diagenetic alteration of other minerals or volcanic glass. GRANT COUNTY: Celadonite is reported from the Bridgeport Quarry, 3 miles SE …
Cerussite
Formula: PbCO3 Orthorhombic Description: Cerussite is formed by the alteration of galena in the presence of carbonate. Heyl et. al. (1959) describe it as a common mineral throughout the zinc-lead district, usually as massive gray to yellowish …
Chalcopyrite
Formula: CuFeS2 Tetragonal Description: Chalcopyrite is an important ore of copper found in a wide range of hydrothermal environments. It is often associated with sphalerite and galena. It oxidizes to form copper minerals such as malachite, azurite, …
Cuprite
Formula: Cu2O Isometric Description: Cuprite, Flambeau Mine, Rusk County, WI. Fibrous chalcotrichite. Vertical field of view is about 0.3 mm. (Image courtesy Dan Behnke, specimen collected by Dan Behnke.) Cuprite generally forms from the alteration of …
Digenite
Formula: Cu9S5 Hexagonal Description: Digenite is a black metallic mineral often found with and mistaken for chalcocite. Both minerals occur in moderate to low temperatures hydrothermal deposits and in supergene enrichment zones. FOREST COUNTY: Digenite occurs sparingly in …
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 …