Formula: PbAl3(PO4)2(OH)5.H2O Hexagonal Description: Plumbogummite is a rare secondary mineral found in the oxidized zone over lead-bearing deposits. RUSK COUNTY: Plumbogummite occurs in the oxidized zone at the Flambeau Mine, near Ladysmith (Jones, Jones, and LaBerge, 1999). …
Wood County
Almandine
Formula: Fe3Al2(SiO4)3 Isometric Description: Almandine is a common garnet found in a many metamorphic rocks such as schist, gneiss, amphibolite and iron formation. It is commonly associated with micaceous minerals such as muscovite, biotite and chlorite and …
Uraninite
Formula: UO2 Isometric Description: Uraninite with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 1134. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew …
Epidote
Formula: Ca2(Al2Fe3+)(Si2O7)(SiO4)O(OH)2 Monoclinic Description: Epidote is a common mineral formed during low grades of metamorphism and hydrothermal activity. It is particular common in metamorphosed basalts and gabbros where it replaces plagioclase, pyroxene and olivine. It can also …
Augite
Formula: (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6 Monoclinic Description: Augite is the most common mineral in the pyroxene family. It has many varieties due to the variation in chemistry possible in its complex coupled solid solution series. Augite is common in gabbroic …
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 …
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 …
Thorogummite
Formula: (Th,U)(SiO4)1-x(OH)4x Tetragonal Description:Thorogummite is formed by the alteration of other thorium-rich minerals, such as thorite. IMA currently lists its status as a species as “doubtful.” MARATHON COUNTY: Much of the thorite found in the pegmatites of the …
Pyrite
Pyrite is the most common sulfide found in many environments. It is a common accessory mineral in igneous, sedimentary and metamorphic rocks. It also is abundant in most hydrothermal deposits. Only the most significant occurrences …
Scheelite
Formula: CaWO4 Tetragonal Description: Scheelite is a high temperature hydrothermal mineral that forms the primary ore of tungsten. WOOD COUNTY: Scheelite occurs rarely as “tiny grayish crystals” in quartz with molybdenite in the Haessley Quarry, Wisconsin Rapids, Wisconsin. …