Formula: ZrO2 Monoclinic Description: Baddeleyite is a rare zirconium oxide found in a variety of environments, including kimberlite, syenite and gabbro. It may survive weathering as a detrital mineral. KENOSHA COUNTY: Baddeleyite occurs as coatings on zircon from …
Kenosha County
Baryte
Formula: BaSO4 Orthorhombic Description:Baryte is found general in low temperature hydrothermal deposits. It is most common in Wisconsin in the Upper Mississippi Valley zinc-lead district in Grant, Iowa, and Lafayette Counties where it is associated with …
Celestine
Formula: SrSO4 Orthorhombic Description:Celestine forms as a groundwater or low temperature hydrothermal precipitate in sedimentary rocks such as limestones and dolostones.IRON COUNTY: Dickey (1938) describes celestine as occurring in small bluish crystals up to 0.3 mm long …
Diamond
Formula: C Isometric Description: Most diamonds form within the earth’s mantle at depths of 100 to 200 km. They are brought to the surface by the action of deep-seated magma which crystallizes to form pipe to …
Diopside
Formula: CaMgSi2O6 Monoclinic Description: Diopside occurs in moderate to high-grade metamorphic rocks. It is particularly common in marbles, calc-silicate rocks, and amphibolites. FLORENCE COUNTY: Found with tremolite in marble from a drill core into a metasedimentary sequence from …
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 …
Ilmenite
Formula: FeTiO3 Hexagonal Description: Black opaque ilmenite with clear quartz, greenish chlorite and high-relief apatite. In rock thin section, viewed in plane-polarized light. Ilmenite grains are about 2 mm in longest dimension. Opelt Quarry, Clark County, Wisconsin. (Photo …
Millerite
Formula: NiS Hexagonal Description: Millerite is a low temperature hydrothermal mineral found in vugs in carbonate rocks and as an alteration product of other nickel minerals. Millerite typically forms long brassy fibers making very aesthetic specimens. …
Phlogopite
Formula: KMg3(AlSi3O10)(OH)2 Monoclinic Description: Phlogopite is a tan mica found most often in magnesium-rich rocks such as marbles, calc-silicate and ultramafic rocks. KENOSHA COUNTY: Phlogopite occurs in a subsurface, diamond-bearing lamprophyre diatreme, discovered within the outskirts of Kenosha …
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 …