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 …
Wood County
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 …
Samarskite-(Y)
Formula: (Y, Fe3+,Fe2+,U, Th, Ca)2(Nb,Ta)2O8 Orthorhombic Description: Samarskite refers to a group of rare oxides found generally as black resinous masses in granitc pegmatites. The decay of radioactive elements in them often renders them metamict. MARATHON COUNTY: Samarskite-(Y) …
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. …
Serpentine
Formula: Mg3Si2O5(OH)4 Monoclinic, orthorhombic, hexagonal Description: Serpentine is a family of polymorphs that include the flaky to platy antigorite, massive lizardite and fibrous clinochrysotile, orthochrysotile and parachrysotile. The polymorphs are often intimately intergrown in a particular rocks, …
Siderite
Formula: FeCO3 Hexagonal Description: Siderite forms as a sedimentary precipitate, in hydrothermal veins, in metamorphic rocks formed from such protoliths, and, rarely, in pegmatites. In sedimentary environments it forms in extensive beds of banded iron formations …
Siegenite
Formula: (Co,Ni)3S4 Isometric Description:Siegenite is an uncommon sulfide of nickel and cobalt found in hydrothermal deposits.WOOD COUNTY: Siegenite has been identified by XRD and EDS analysis of small gray metallic xls. found at the Frederick Schill Quarry, north …
Sphalerite
Formula: ZnS Isometric Description: Banded sphalerite, near Hazel Green in Lafayette County, Wisconsin. Sample is about 1 cm long. Sphalerite occurs in a wide range of hydrothermal environments. It is common with chalcopyrite in exhalative massive …
Talc
Formula: Mg3Si4O10(OH)2 Triclinic Description: Talc with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 1073. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew …
Thorite
Formula: (Th,U)SiO4 Tetragonal Description:Thorite is a rare mineral found in pegmatites and hydrothermal deposits.MARATHON COUNTY: Thorite is found in the pegmatites associated with the amphibole syenites of the Stettin pluton. Some grains and clusters may be several centimeters …