Formula: Ca2Al2Si3O10(OH)2 Orthorhombic Description: Prehnite in vug in basalt, with dark marcasite crystals. Buckley quarry, Douglas County, WI. field of view about 6 cm. across. (Photo by W. Cordua) Prehnite is most often found as a vein or …
Bayfield County
Pumpellyite Group
Formula: Ca2(Fe2+,Mg)Al2(SiO4)(Si2O7)(OH)2.H2O Monoclinic Description: Pumpellyite is used to denote a group of closely related minerals that form during relatively low grade burial metamorphism. It is often associated with prehnite, epidote and chlorite. It is most common …
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 …
Silver
Formula: Ag Isometric Description:Native silver is found in hydrothermal veins or, more rarely, as a supergene mineral. It is associated with gold, and a variety of sulfides such as galena, pyrite and acanthite. Major silver mineralization …
Stilpnomelane
Formula: (K,Ca,Na)(Fe, Mg,Al)8(Si,Al)12(O,OH)36.nH2O Triclinic Description: Stilpnomelane is a brown micaceous to velvety to fibrous mineral found in various metamorphic rocks, especially those rich in iron. It often occurs with chlorite, epidote, magnetite, hematite and goethite and …
Tremolite
Formula: Ca2Mg5Si8O22(OH)2 Monoclinic Description: Tremolite marble from Florence County, Wisconsin. Field of view 7 cm across. (Photo by Al Falster.) Tremolite is formed by the metamorphism of calcium-rich rocks such as limestone and dolostone. It occurs in numerous …
Zircon
Formula: ZrSiO4 Tetragonal Description: Zircon in tabular crystal from the Nine Mile Pluton near Wausau in Marathon County, Wisconsin. Scanning electron microscope image. (Photo by Al Falster.) Zircon is a common accessory mineral found in many different …
Zoisite
Formula: (Th,U)SiO4 Tetragonal Description: Thorite is a rare mineral found in pegmatites and hydrothermal deposits. Zoisite is formed in rocks subjected to low to medium grade metamorphism. If often results from the deterioration of plagioclase. It is …
Inventory and Analysis of Flowing Artesian Wells in Bayfield County, Wisconsin
This report presents a county-wide inventory of flowing artesian wells in Bayfield County. Flowing artesian wells are a remarkable resource of high-quality water that both community members and tourists value. This report provides baseline water …
Hydrogeology of the sandy uplands of the Bayfield Peninsula, Wisconsin
The sandy uplands of the Bayfield Peninsula are primary contributors to regional groundwater recharge and provide baseflow to streams in the area. Few data exist, however, to characterize upland hydrogeology or its susceptibility to groundwater …