Formula: CaAl3(PO4)2(OH)5.H2O Hexagonal Description: Crandallite is used here to refer to a group of minerals in the Crandallite group, including florencite. Crandallite itself is formed by groundwater precipitation in sedimentary rocks and soils as a result …
Rusk County
Cuprite
Formula: Cu2O Isometric Description: Cuprite, Flambeau Mine, Rusk County, WI. Fibrous chalcotrichite. Vertical field of view is about 0.3 mm. (Image courtesy Dan Behnke, specimen collected by Dan Behnke.) Cuprite generally forms from the alteration of …
Digenite
Formula: Cu9S5 Hexagonal Description: Digenite is a black metallic mineral often found with and mistaken for chalcocite. Both minerals occur in moderate to low temperatures hydrothermal deposits and in supergene enrichment zones. FOREST COUNTY: Digenite occurs sparingly in …
Dzhalindite
Formula: In(OH)3 Isometric Description: Dzhalindite is a rare mineral found with other indium minerals. RUSK COUNTY: Dzhalindite occurs as microscopic black grains with chalcocite at the Flambeau Mine, near Ladysmith (Jones, Jones, and LaBerge, 1999).
Ferristrunzite
Formula: Fe2+Fe3+2(PO4)2(OH)3.5H2O Triclinic Description: Ferristrunzite is a rare phosphate mineral formed by the alteration of other phosphates. RUSK COUNTY: Ferristrunzite is found as bright yellow acicular crystals arranged in radial clusters in vugs and seams in massive …
Gahnite
Formula: ZnAl2O4 Isometric Description: Green gahnite crystal on quartz. From Waterloo quarry, Dodge County, Wisconsin. Field of view is 1 mm left to right. (Image courtesy Dan Behnke, specimen collected by Tom Buchholz.) Gahnite is an uncommon …
Galena
Formula: PbS Isometric Description: Galena crystals surrounded by marcasite, from Shullsburg, Wisconsin. (Image courtesy W. S. Cordua.) Galena is formed in a wide range of hydrothermal environments. It can be found with sphalerite and chalcopyrite in …
Glaucodot
Formula: (Co0.5Fe0.5)AsS Orthorhombic Description: Rare gray metallic copper, iron and arsenic sulfide found in hydrothermal deposits. RUSK COUNTY: Occurs either as pseudo-isometric crystals or as coatings on or pseudomorphs after pyrite, from the Flambeau Copper Mine, Ladysmith. …
Goethite
Formula: FeO(OH) Orthorhombic Description: Stalactitic goethite from Montreal Mine in Iron County, Wisconsin. (Image courtesy W. S. Cordua.) Goethite is a common iron mineral. It often forms by weathering of other iron-rich minerals, thus is a …
Gold
Formula: Au Isometric Description:Gold is usually found in hydrothermal deposits where it forms at a wide range of temperatures and geological settings. Gold may form in exhalative deposits formed on the sea floor associated with Archean …