Formula: CaSO4 Orthorhombic Description: Anhydrite is a relatively common mineral usually formed as a chemical precipitate from saline water in limestone, dolostone, and salt beds. Its presence is obscured by its tendency to dissolve or be altered …
Sauk County
Ankerite
Formula: Ca(Fe,Mg,Mn)(CO3)2 Hexagonal Description: Ankerite is formed as a sedimentary precipitate, a groundwater and hydrothermal precipitate and by metamorphic recrystallization of iron-rich sedimentary rocks. ASHLAND COUNTY: Ankerite is a component of the Ironwood iron formation in the Penokean …
Apatite Group
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 …
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 …
Chalcocite
Formula: Cu2S Monoclinic Description: Chalcocite is formed either as a primary vein mineral or, more typically, in supergene deposits where it forms as a result of the redeposition of copper from the breakdown of minerals such …
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, …
Chlorite Group
Formula: (Al, Fe, Li, Mg, MN, Ni, Zn)6 (Si, Al)4O10(OH, O)2 MONOCLINIC or TRICLINIC Description: Chlorite represents a group of over 10 minerals related by complex solid solution substitutions. These minerals are generally fine-grained, micaceous and dark green. …
Diaspore
Formula: AlO(OH) Orthorhombic Description: Diaspore occurs as platy masses in highly aluminous metamorphic rocks associated with corundum. It is a common component of emery. Diaspore also is a common component of bauxite, aluminous soils and clays. …
Dickite
Formula: Al2Si2O5(OH)4 Monoclinic Description: Dickite is a clay mineral having the same formula as kaolin, nacrite and halloysite but a different crystal structure. It is found intergrown with other clay minerals. It requires x-ray diffraction for positive …
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 …