Formula: Ca2(Mg,Fe)5Si8O22(OH)2 Monoclinic Description: Actinolite is a common member of the amphibole family. It typically forms during low-grade metamorphism of mafic igneous rocks (such as basalt and gabbro) or carbonate-rich rocks such as limey mudstones. ASHLAND COUNTY: Van …
Wood County
Allanite
Formula: (Ce,Ca,Ce,La,Nd,Y)2(Al,Fe)3(Si2O7)(SiO4)O(OH) Monoclinic Description:Allanite refers to a group of minerals found as an accessory in a number of different rocks such as syenite, granite and gneiss. It may also be a component of granite pegmatite. It …
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 …
Anatase
Formula: TiO2 Tetragonal Description: Anatase is a relatively rare mineral found in veins and cavities in schists, gneisses, granites, syenites and other related igneous rocks. It is also a product of weathering of other titanium minerals. Tyler …
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 …
Anthophyllite
Formula: (Mg,Fe)7Si8O22(OH)2 Orthorhombic Description: Anthophyllite is a mineral formed from the metamorphism of magnesium-rich rocks. It is often associated with other amphibole minerals, pyrope, and cordierite. JACKSON COUNTY: Anthophyllite occurs as long radiating fibrous crystals and masses intergrown …
Apatite Group
Formula: Ca5(PO4)3(F,Cl,OH) Hexagonal Description:Apatite denotes a family of minerals referred to variously in older literature as “fluorapatite,” “chlorapatite,” “carbonate-apatite” or “hydroxlyapatite” and in newer literature as apatite- (CaF) etc. depending on which anion group dominates. Members …
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 …
Azurite
Formula: Cu3(CO3)2(OH)2 Monoclinic Description: Azurite is an attractive blue mineral found as a secondary weathering and supergene mineral formed from the alteration of native copper and other copper minerals. It is often found associated with and altering …
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 …