Formula: Fe2O3 Hexagonal
Hematite is an extremely common mineral. It can form as a sedimentary precipitate, a product of weathering of other iron rich minerals in soils and oxidized zones of ore deposits, as a primary mineral in hydrothermal veins, and as a metamorphic mineral. Only a few of its many occurrences in Wisconsin are noted here.
ASHLAND COUNTY: Hematite forms in the Penokee Range as a principle ore mineral in the Ironwood Iron Formation. Van Hise and Leith (1911) describe the ore as containing soft red hematite (paint ore) mingled with harder red slatey hematite and steel blue hematite nodules. Botryoidal, banded, oolitic and coarsely columnar needle ore also occur. The hematite, in conjunction with other iron oxides replace iron carbonates in the ore. Associated minerals include siderite, magnetite, chamosite and stilpnomelane (U.S.G.S., 1976). A typical outcrop is near Mellen in the SW SW SE Sec. 9 T.44N R.2W (Mudrey, 1979).
— Specular hematite is found on the dumps and in the workings of the Michigan iron mine in T.42N R.1E about 10 miles NE of Butternut. Associated minerals are magnetite and quartz (U.S.G.S., 1976).
BROWN COUNTY: Oolitic hematite of the Neda iron formation is exposed on the north side of Hwy. G at Kittell Falls near Bellevue (SE NE Sec. 32 T.23N R.21E). Here it is interbedded with shales and dolostones and associated with pyrite (Ostrum, undated WGNHS outcrop description; Paull and Emerick, 1991).
DANE COUNTY: Nodules of hematite up to 5 cm. in diameter have been found on a farm northeast of Mt. Horeb (NE Sec. 16 T.6N R.7E) (Habermann, 1978).
DODGE COUNTY: Sedimentary hematite formed the ore of the Neda Formation (Mayville or “Clinton iron ore beds”) at several places in the county. The hematite is red to black, oolitic to massive, earthy to hard. It was associated with goethite and an array of phosphate minerals (Chamberlain, 1877, Hawley and Beavens, 1934; U.S.G.S., 1976; Paull, 1977). It was mined along Iron Ridge near Mayville in Sec. 12 and 13 T.11N R.16E until the mid-1970’s. Beds up to 55 feet thick occurred. It is also exposed in the E 1/2 NW Sec. 1 T.11N R.16E, east of Neda (Paull, 1977) and near Hartford and Stockbridge (U.S.G.S., 1976). Lawson (1906) describes an outcrop of hematite ore 5 feet thick at Cascade Falls, east of Depere.
FLORENCE COUNTY: Hematite occurs at a number of places throughout the county in scattered outcrops of iron formation. – Massive earthy hematite forms as a result of weathering of primary magnetite in iron formation exposed in the SW NE Sec. 28 T.39N R.18E (Dutton, 1971).
— Hematite is common as soft massive material in the weathered Riverton iron formation where it replaces siderite and magnetite, and occurs with grunerite and stilpnomelane. Dutton (1971) lists numerous mines and prospects in T.40N R.18E. These include the Florence Mine (Sec. 20 and 21), the St. Clair Shaft (SW NW Sec. 24), the Ernst mine (SW SW Sec. 37), the Badger Mine (SE SE Sec. 34), the Commonwealth Mine (NE SW Sec. 34), and the Davidson Mine (NE SW Sec. 34).
— Hematite occurs as specularite and “martite” pseudomorphs after magnetite in the conglomerate facies of the Pine River Conglomerate at the Pine River Reservoir, 5 miles south of Florence. It also occurs in quartz veins with kyanite (Nielsen, 1964). Hematite occurs as a component of certain slates within the Michigamme Slate at the Spread Eagle exploration pits in Sec. 8 and 9, T.39N R.19E (Dutton, 1971).
FOREST COUNTY: Hematite occurs as a minor alteration mineral in the Crandon massive sulfide deposit near Little Sand Lake (Lambe and Rowe, 1989).
IOWA COUNTY: Red ocherous hematite used as paint was found in the upper beds of the St. Peter sandstone in the Centerville District, SW Sec. 7 T.6N R.1E (Strong, 1873).
IRON COUNTY: Hematite forms in the Penokee Range as a principle ore mineral in numerous mines in the Ironwood Iron Formation. Van Hise and Leith (1911) describes the ore as containing soft red hematite (paint ore) mingled with harder red slatey hematite and steel blue hematite nodules. Botryoidal, banded, oolitic and coarsely columnar needle ore also occur. The hematite, in conjunction with other iron oxides, replace iron carbonates. Associated minerals include siderite, magnetite, chamosite and stilpnomelane (U.S.G.S., 1976). The most famous mine in the range is the Montreal Iron Mine (Sec. 33 T.46N R.2E) where large globular to botryoidal masses and bladed “needle ore” crystals up to 1 foot long occur(LaBerge, 1984). Abundant large botryoidal masses and needle ore also occur at the nearby Cary Mine workings (NW NE Sec. 26 T.40N R.2E). Other major mines in the belt producing hematite are at Tyler’s Fork (E 1/2 Sec. 33 T.45N R.1W) and at Iron Belt (NE sec. 11 T.45N R.1E).
— Hematite occurs with siderite in cherty iron formation in exploration pits near Pine Lake in Sec. 23, 26, 27 and 28 T.44N R.3E (Dutton and Bradley, 1970).
— Hematite is found in iron formation exposed in pits near Butternut in Sec. 21, 28 and 29 T.41N R.1W (Dutton and Bradley, 1970).
JACKSON COUNTY: Hematite is common at the Jackson County Iron Mine (SE Sec. 15 T.1N R.3W) especially along the unconformity between the Precambrian iron formation and the Cambrian Mt. Simon sandstone (Jones, 1977).
— Hematite is found as “martite” pseudomorphs after magnetite in iron formation outcropping on mounds in the Black River Falls area such as in the NE Sec. 12 and SW SE Sec. 11 T.21N R.4W (Klemic and Olson, 1973).
JUNEAU COUNTY: Small roses of hematite crystals occur with quartz crystals. in vugs in quartzite in the Necedah Bluff quarry NE Sec. 24 T.18N R.3E (Buchholz, 1993, personal communication).
LAFAYETTE COUNTY: Hematite is abundant at “Red Rock” in Sec. 17 T.2N R.4E SE of Darlington. Here it occurs as interstitial material in the St. Peter Sandstone. It likely forms from the alteration of disseminated pyrite and marcasite (Heyl et. al., 1959).
— Pebbles of hard dark red to gray hematite occurs in regolith in ravines southeast of Hazel Green such as in SE SW Sec. 30 and NW NW Sec. 32 T.1N R.1E (Heyl et al., 1959).
MARATHON COUNTY: Microscopic euhedral hexagonal prisms of hematite occur intergrown in microcline microperthite in the granitic rocks of the Nine Mile Pluton. Some good outcrops are in Sec. 6 T.28N R.7E and Sec. 16, 17, and 33 T.29N R.7E (LaBerge and Myers, 1983). -Rosettes of hematite crystals resembling the iron roses” of the Alps are found in cavities of the pegmatites of the Wausau Pluton, such as are exposed in the “rotten” granite quarries south of Rib Mt. (Falster, 1987; Buchholz, Falster and Simmons, 1999, Falster et al., 2000).
— Hematite occurs as veins of specular material cutting granite in the the Ladick Quarry (sec. 19 and 20 T. 27N. R.6E.) (Cordua, personal observation)
OCONTO COUNTY: Flakes of specular hematite are found with quartz crystals on Mount McCaslin (T.33N R.15E), approximately 3.3 miles north of Townsend on Route 32 (Eckert, 1980).
PIERCE COUNTY: Hematite is found as masses and botryoidal crusts with goethite at the Cady Creek iron mine, about 5.5 miles SE of Spring Valley (SW NE SW Sec. 14 T.27N R.15W) (Rosenberg, 1991; Allen, 1909).
Masses and botryoidal crusts of hematite with goethite occur at the Gilman Mine about 1.5 miles west of Spring Valley (NE SW SW Sec. 1 T.27N R.16W) (Rosenberg, 1991; Allen, 1909).
RICHLAND COUNTY: Several small iron mines were developed in hematite-rich compact red clays near Richland Center in SW Sec. 7 and SE Sec. 30 T.10N R.1E. A similar deposit was mined near Boaz in the NW Sec. 12 T.10N R.1W (Heyl et al., 1959).
RUSK COUNTY: Hematite is a component of the gossan cap with other secondary iron and copper minerals at the Flambeau deposit, near Ladysmith (May, 1977).
— Hematite occurs as “massive, layered or irregularly finely crystalline material” and as “martite” pseudomorphs after magnetite in prospect pits in quartz-sericite schist in SW Sec. 10 T.34N R.8W, east of Weyerhauser (Dutton and Bradley, 1970).
SAUK COUNTY: Hematite was widespread in the iron mines of the Baraboo district. The hematite was found in the dolomitic and ferruginous slates of the Freedom formation intermixed with goethite, quartz, kaolin, chlorite, siderite, dolomite and “iron phosphates.” The hematite occurred as hard black, soft earthy and banded siliceous masses (Leith, 1904). The following mines in T.11N R.5E near North Freedom, were listed in Rohn (1903): the Wisconsin Mine, SE Sec. 10, the Sauk Mine, NE Sec. 10, the LaRue Property, SW Sec. 16, the Illinois Mine, E 1/2 Sec. 16, the Judeville Property, SW Sec. 17, the Patterson Property, NW Sec. 20.
— Small veins of quartz and specular hematite in the Baraboo quartzite are widespread in Baxter Hollow and in the Upper Narrows near Rock Springs (Gates, 1942).
— Hematite is associated with malachite and chalcopyrite in brecciated Cambrian sandstone on the upper east side of Hagerman Hill, Sec. 34 T.13N R.3E, about 2 Km. south of LaValle (Heyl and West, 1982). A hematite-rich compact clay was mined near LaValle in the NW Sec. 18 T.13N R.2E.
— Botryoidal to stalactitic hematite occurs with goethite in the interstices of sandstone at the old Ironton Iron Mine in the SW Sec. 10 T.12N R.3E (U.S.G.S., 1976; Irving, 1883c). Irving speculates that this was derived from the oxidation of iron sulfides.
— Hematite as rosettes on quartz crystals occur in hydrothermal breccias at the Martin-Marietta Aggregates Quarry at Rock Srpings (Brown, et al., 2001)
VERNON COUNTY: A compact red clay was mined for iron near Readstown in NW Sec. 18 T.11N R.3W (Heyl et al., 1959).