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). …
Rusk County
Hematite
Formula: Fe2O3 Hexagonal Description: “Needle Ore” hematite, longest needle is about 20 cm long. From Montreal Mine in Iron County, Wisconsin. (Photo by W. Cordua.) Hematite is an extremely common mineral. It can form as a sedimentary precipitate, …
Beaverite-(Cu)
Formula: Pb(Fe3+Cu)3(SO4)2(OH)6 Hexagonal Description: Beaverite-(Cu) is a rare secondary mineral found in the oxidized zone over lead-bearing deposits. RUSK COUNTY: Beaverite occurs as in the oxidized zone at the Flambeau Mine, near Ladysmith (Jones, Jones, and LaBerge, 1999).
Hessite
Formula: Ag2Te Monoclinic Description: Hessite is a silver telluride forming masses or pseudo-cubic crystals in hydrothermal deposits. RUSK COUNTY: Hessite was reported as tiny grains intergrown with other sulfides in the primary ore at the Flambeau Copper …
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 …
Tetrahedrite-tennantite
Formula: (Cu,Fe,Ag,Zn)12(Sb,As)4S13 Isometric Description:Tetrahedrite forms a solid solution series with tennantite and freibergite in moderate to low temperature hydrothermal deposits. DOUGLAS COUNTY: Irving (1882) reports finding tetrahedrite in “small quantities in traverse veins in copper-bearing rocks”. This occurrence …
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 …
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, …
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 …
Osarizawaite
Formula: Pb(AlCu)3(SO4)2(OH)6 Hexagonal Description: Osarizawaite is a rare secondary mineral found in the zone of oxidized over lead-bearing deposits. RUSK COUNTY: Osarizawaite occurs in the oxidized zone at the Flambeau Mine, near Ladysmith (Jones, Jones, and LaBerge, 1999).