Formula: SiO2 Hexagonal
Quartz is the most abundant mineral. It is an essential component of granitic igneous rocks, of sedimentary rocks such as sandstone and chert and of metamorphic rocks such as quartzites. It is a common hydrothermal mineral and forms in amygdules in volcanic rock, sometimes in the form of Lake Superior agate. It forms as a groundwater precipitate, and can form sparkling crystals lining cavities in quartzite, limestone and dolostone. Quartz also forms the bulk of unconsolidated sediments such as drift and alluvium, where it can be found occasionally as Lake Superior agates freed from their volcanic matrix by erosion. There are few places in the state that don’t have quartz in some form. Only the most important or unusual occurrences of quartz are mentioned here.
ADAMS COUNTY: Red and green banded quartz and, locally, small crystals, occur in folded quartzite and quartz breccia in outcrops and quarries at Hamilton Mounds in Sec. 36 T.20N. R.6E. and Sec. 31 T.20N. R7E (Greenberg et al., 1986).
ASHLAND COUNTY: Quartz as “Lake Superior Agate” is widespread in gravel pits throughout the county, as well as along beaches, such as those of the Apostle Islands (Eckert, 1980).
—Quartz is the major component, with chlorite, biotite and actinolite of the Sunday Quartzite throughout the Penokee Range.Fine cherty to coarse granular quartz is also common in the Bad River Dolomite throughout the Penokee Range where it is associated with calcite, dolomite, tremolite, sericite, pyrite and magnetite. Outcrops of these rocks can be found on the N side of the Bad River at Penokee Gap (Sec. 14 T44N R3W) (Van Hise and Irving, 1892).
BARRON COUNTY: Quartz is the major component of the Barron quartzite exposed throughout the Blue Hills region such as Sec. 3-6 T34N R10W, Sec. 12-15, 21-23 and 27-36 T35N R10W (Hotchkiss, 1915).
BAYFIELD COUNTY: Fine cherty to coarse crystalline quartz is common in the Bad River Dolomite throughout the Penokee Range where it is associated with calcite, dolomite, sericite, pyrite and magnetite. Some localities are in the marble quarry NW NW NW Sec. 22 T.44N. R.5W and near the Marengo River, SE Sec. 15 T44N R5W (Van Hise and Irving, 1892; Mudrey, 1979).
—Quartz is abundant as white crystals and small pink to orangish agates in amygdules with chlorite, epidote, K feldspar and bornite in Keweenawan basalts in the south halves of Sec. 4 and 5, T.44N. R.6W., south of Grandview (W. S. Cordua field notes).
—Quartz as agate occurs in amygdules with laumontite, calcite, pyrite, K feldspar, chlorite and epidote in Keweenawan basalts in Sec. 21 and 22 T43N R7W in outcrops along the Namakagon River near Cable (Strong, 1880).
BUFFALO COUNTY: Quartz is common as drusy clear, white and red crystals in vuggy zones in the Prairie du Chien Group dolostones throughout the county. Some localities are in a quarry west of Cream NW NW Sec. 24 T22N R12W, and quarries east of Cochrane in Sec. 3 and Sec. 14 T20N R12W Also banded gray to brown agate rinds up to 1 cm thick lining quartz crystal vugs in Prairie du Chien dolostones in a small quarry on County I, 4 miles NE of Nelson, NW Sec. 35 T22N R13W (W. S. Cordua field notes, 1992).
BURNETT COUNTY: Quartz is the major component of sandstone (likely the Cambrian Mt. Simon Formation) exposed at several spots along the St. Croix River both north and south of the Hwy. 70 bridge over the river, west of Grantsburg. The most accessible outcrop is at Sandrock Cliffs, a national park service campground in sec. 7 T38N R19W. The formation is also mined for frac sand near Grantsburg.
CALUMET COUNTY: Fossils silicified by quartz can be found in a quarry in dolostone approximately 2 miles N of Sturgeon Bay (Soderman and Carozzi, 1963).
CHIPPEWA COUNTY: Quartz as Lake Superior agates are found in gravel pits near Chippewa Falls (Eckert, 1980). – Quartz is the major component of the Flambeau Quartzite exposed in SE Sec. 1, SW Sec. 2, in a small quarry at NE NE Sec. 11 T32N R7W, and in the SE SW Sec. 6 T32N R6W NW of Holcombe. Quartz is also found in gash veins cutting the quartzite, occasionally forming slender euhedral crystals several cm in length (Campbell, 1981).
CLARK COUNTY: Quartz as Lake Superior agates are found in gravel pits and sand bars along the Black River (Eckert, 1980).
—Quartz are well-cemented, iron oxide mottled sandstone known as Zebra sandstone occurs at Wildcat Mount, about 4 miles E of Humbird (SE SW Sec. 25 T24N R19W) (WGNHS Files).
COLUMBIA COUNTY: Quartz crystals several inches long occur in vugs in a hydrothermal breccia exposed in the Williams Quarry, SE NE sec. 19 T.12N. R.8E, east of Baraboo. (Brown et al., 2001)
CRAWFORD COUNTY: Quartz as Lake Superior agates are found in gravel pits near Prairie du Chien (Eckert, 1980).
DANE COUNTY: Quartz sand from friable St. Peter sandstone is mined at Klevenville (Paull and Paull, 1977).
DODGE COUNTY: Quartz is the major component of the Waterloo quartzite, where it is associated with sericite and chlorite. It is well exposed in the Michel Materials Quarry, SE Sec. 33 and SW Sec. 34 T9N R13E east of Portland, at Rocky Island NE of Portland and about 4 km SE of Reeseville (Brown, 1986; Brown et al., 2002).
—Fossils silicified by quartz occurs in Silurian dolostone in a quarry approximately 3 km N of Knowles (Soderman and Carozzi, 1963). quartz is abundant at the Micheals Materials quarry 1.5 miles east of Portland, where it occurs in quartzite, quartz veins and pegmatites (Brown et al., 2001).
DOOR COUNTY: Quartz occurs as drusy crystals filling voids in brachipod shells, also as chalcedonic masses, locally botryoidal with vugs containing small fluorite and dolomite xls. in a quarry in Sturgeon Bay. (Carl Cochrane, 1999, personal communication)
DOUGLAS COUNTY: Geodes of quartz in epidote-rich rock is reported at the quarter post between Sec. 28 and 33 T43N R10W near Wascott (Strong, 1880).
—White, blue, red and smokey quartz, as well as pale pink to tan agates, occur in amygdules in Keweenawan basalt at the South Range Quarry, NW NW Sec. 1 T.47N. R.13W. The quartz is massive and as crystals. Associated minerals include epidote, calcite, prehnite, chlorite, chalcopyrite and potassium feldspar (Cordua, 1990).
—Small agates in basalt are found at the Mabel Nelson quarry, south of South Range. (W. S. Cordua, 1990 field notes).
DUNN COUNTY: Quartz as Lake Superior agates are widespread in gravel deposits near Menomonie (Eckert, 1980).
EAU CLAIRE COUNTY: Quartz as attractive iron oxide spotted quartz sandstone known as “zebra sandstone” outcrops near Fairchild (WGNHS files).
FLORENCE COUNTY: Quartz is a component of the lithium-rich complex pegmatites in Sec. 22 T39N R17E where it is associated with albite, microcline, muscovite, elbaite, columbite-tantalite, beryl and other rare minerals (Koehler, 1991).
—Quartz is found with molybdenite at the Payout-Chrissman prospect along Fisher Creek, Sec. 33 T38N R19E near Aurora (Fisher, 1965).
FOND DU LAC COUNTY: Quartz-rich St. Peter sandstone is quarried on a large scale by the Badger Mining Corp. at the Fairwater Quarry (SW NE Sec. 36 T15N R13E) SW of Ripon (UW Oshkosh, 1994).
FOREST COUNTY: Quartz is the major constituent of the quartzite of McCaslin Mountain where it also occurs as large crystals and clusters locally in veins. Major outcrops are in Sec. 33-36 T.34N. R.16E. (Eckert, 1980). Quartz Hill is well known as a locality for collecting quartz crystals either loose in the soil or in vuggy veins cutting quartzite. Crystals, which may be several centimeters long, are white to clear and may be doubly terminated (Beard, 2002)
—Quartz is abundant in veins and silicified country rock in the Crandon massive sulfide deposit (May and Schmidt, 1982).
GRANT COUNTY: Quartz as “Lake Superior Agate” is found in gravel pits in the Cassville area and the Muscoda area (Eckert, 1980).
GREEN LAKE COUNTY: Milky, red, brown and pink quartz as drusy crystal crusts is found in cavities in Ordovician Prairie du Chien Group dolostones at several localities. These include at Mt. Tom in Sec. 11 T16N R12E and near Brooklyn in Sec. 14 T16N R12E (Chamberlain, 1877). The dolostone in the Morris Pit contains drusy quartz crystals as well as brown to orange jasper, and thin pink to orange to white banded “cold water” agates termed “Nolte agate” by local rockhounds (Ponzio, 2010).
—Tiny phenocrysts of quartz occur with pink K feldspar in black aphanitic matrix in the Utley rhyolite tuff. This rock is well-exposed in the quarries in NW SW NE Sec. 36 T14N R13E just west of Fairwater (WGNHS outcrop description; UW Oshkosh, 1994).
IOWA COUNTY: Silicification of Prairie du Chien group rocks is widespread in the Upper Mississippi Valley zinc-lead district where it is prevalent along faults and fractures. This forms massive jasperoid as well as drusy crystals. Several major mines in the county showing this are the Demby-Weist mines about 12 miles NE of Dodgeville (NW Sec. 28 and SW Sec. 21 T7N R4E) and the Ohlerking Mine near Highland (NW SE Sec. 31 T7N R1E) (Heyl et al., 1959).
IRON COUNTY: Quartz is the major component of the Sunday quartzite throughout the Penokee Range. Some localities are in Sec. 33 and 34 T.45N. R.1W at Tyler’s Fork, in Sec. 27 T46N R2E near Montreal and in sec 24 T.46N. R.2E. at the Germania Mine (Van Hise and Irving, 1892).
—Silicified rhyolite containing “thunder eggs” occurs at an undisclosed locality in the County. The quartz formed drusy crystals and pale banded agate fillings, associated with fluorite and clay minerals within the “thunder eggs.”
JACKSON COUNTY: An attractive quartz sandstone called “zebra sandstone” mottled with reddish-brown iron oxides occurs at several places in Jackson County. Some localities are SW corner Sec. 27 T.23N. R.5W. 3 miles west of Alma Center, and at Stanley Mound SW SE Sec. 34 T.23N. R.4W. about 2 km. S of Merrilan (WGNHS files).
—The Cambrian Wonewoc sandstone exposed at Silver Mound (SW Sec. 35 T23N R5W) is so well cemented by silica that is was used by prehistoric Native Americans to make tools (Klemic and Olson, 1973).
—Massive vein quartz and drusy crystals are abundant in quartzite and quartz breccia in the Battle Point Road Quarry, NW Sec. 9 T21N R2W. The crystals are clear to milky to locally iron oxide stained and may be several cm long (Klemic and Olson, 1973; W. S. Cordua field notes, 1993).
JEFFERSON COUNTY: Quartz is the major component of the Waterloo quartzite, as exposed in the Lake Mills area S of Waterloo (Brown, 1986).
JUNEAU COUNTY: Quartz is the major component of the quartzite at Necedah Bluff, well exposed in the quarries in NE Sec. 24 T18N R3E. The quartz is grey, pink and green and also occurs as milky crystals 3 cm long in veins. Some “C Face” quartz crystals have been found. Associated minerals include K feldspar and sericite (Greenberg, et al., 1986). Small hematite roses occur perched on the quartz crystals (Buchholz, personal communication, 1993).
LA CROSSE COUNTY: Quartz as “Lake Superior agate” occurs in gravel pits and river sand bars near La Crosse (Eckert, 1980).
LAFAYETTE COUNTY: Fine-grained “jasperoid” occurs in the zinc-lead mines in the Cuba City, New Diggings and Shullsburg area (Mullens, 1964). Small drusy crystals are noted from the Thompson-Temperly Mine on the SW edge of New Diggins (Hostermann, Heyl and Jolly, 1964).
—Quartz is the major constituent of the quartzite of McCaslin Mountain where it also occurs as large crystals and clusters locally in veins. Major outcrops are in Sec. 33-36 T.34N. R.16E. (Eckert, 1980).
MANITOWOC COUNTY: Quartz replacing fossils occurs in the Niagara Formation in the NW NW Sec. 5 T19N R22E (W. S. Cordua field notes).
MARATHON COUNTY: Clear to smokey crystals up to 80 cm long, some doubly terminated and often distorted and etched are common in miarolitic cavities in the mineralogically complex pegmatites of the Nine Mile Pluton. These are commonly exposed in the granite quarries south of Rib Mountain in Sec. 19 and 20 T28N R7E (Falster, 1987; Myers et al., 1984; Falster et al., 2000), in Sec. 6 T28N R7E, NW Sec. 33 T29N R7E and Sec. 16 and 17 T29N R7E (LaBerge and Myers, 1983).
—Quartz is the most abundant constituent of the Rib Mountain Quartzite, such as is well exposed in Sec. 8 and 9 T28N R7E (Myers et al., 1984). This quartzite is also well exposed on Mosinee Hill, especially in the quarry in NE NE Sec. 27 T28N R7E. Another important outcrop occurs 1 mile N of the Stettin Road bridge over the Little Rib River in the NE Sec. 29 T29N R7E where quartz is intergrown with muscovite and sillimanite (LaBerge and Myers, 1983).
MARINETTE COUNTY: Quartz with a distinctive light blue color occurs in tonalite along railroad tracks approximately 1 mile W of Pembine. Associated mineral include K feldspar, muscovite and chlorite (Depangher, 1982).
—Quartz occurs with molybdenite at the Camp Five deposit about 4 miles NW of Middle Islet, Sec. 18 T.33N. R.20E. (Fisher, 1965).
—Grey and smokey quartz occur in veins with pyrite and tourmaline at the contact of the Spikehorn granite and in an inclusion of Quinnesec volcanics in outcrop in NW Sec. 1 T.37N. R.20E. north of Pembine (Sims, Schulz and Peterman, 1984).
MILWAUKEE COUNTY: Chalcedony geodes up to 8 cm across occur at the Estabrook Park millerite locality along the Milwaukee River Sec. 5 T7N R22E (Eckert, 1980).
MONROE COUNTY: Quartz as drusy clusters having a pale amethyst color are reported from Prairie du Chien dolostone near Sparta (Crowns, 1976).
OCONTO COUNTY: Quartz is the major component of the McCaslin quartzite. The quartzite is also cross-cut by being with well-developed quartz crystals and hematite. One well-known locality is as vein quartz along a NW-SE fault zone exposed near Route 32 approximately 3.5 miles N of Townsend (Eckert, 1980; Olson, 1984).
OUTAGAMIE COUNTY: Drusy quartz crystals with a pleasant red color, called by collectors “raspberry quartz”, is found in Prairie du Chien dolostones in the Brugger Road Quarry, south of Nichols (Carl Cochrane, 1998, personal communication).
PEPIN COUNTY: Quartz as “Lake Superior agate” is found in gravel pits west of Durand and along the shore of Lake Pepin (Eckert, 1980).
—Quartz occurs as thin-shelled geodes up to 10 cm filled with drusy crystals in a quarry on Big Hill Road, NE of Pepin in SE NE NE Sec. 17 T.23N. R.14W. (W. S. Cordua field notes).
—Drusy quartz and small geodes occur in Prairie du Chien dolostone at the Fayerweather Quarry, north of Stockholm (NW NW sec. 7 T.23N. R.15W.) Excellent pseudomorphs of goethite after pyrite and marcasite are associated. (W. S. Cordua field notes).
PIERCE COUNTY: Quartz as “Lake Superior agate” is found in numerous gravel pits throughout the county and on gravel bars along the St. Croix and Mississippi Rivers. Gravel bars along the Rush River near Plum City and along the Kinnickinnic River near River Falls yield significant amounts of agates (Eckert, 1980; W. S. Cordua field notes).
—Drusy quartz clusters and agate rinds are found in cavities in the Prairie du Chien Group dolostones in a number of areas. One locality is along Hwy 72 on the W side of Cave Creek near Waverly (SW SE Sec. 15 T.25N. R.16W. (W. S. Cordua field notes). Another is in the quarry E of Maiden Rock in NW Sec. 14 T.24N. R.16W. (Cordua, 1989a). Such crystals also occur in the quarry west of the Rush River along Hwy 10 in NE Sec. 5 T.25N. R.16W. (W. S. Cordua field notes). Crystals are also found in the roadcuts along County Q (NW Sec. 27 T.26N. R.19W.). The quarry south of Elmwood (SE SE Sec. 36 T.27N. R.15W.) contains drusy quartz with thin agate rinds (W. S. Cordua field notes). Associated minerals at these sites are dolomite, calcite, and goethite pseudomorphs after pyrite and marcasite. Drusy quartz crystals and agate rimmed vugs occur in a quarry on County VV N of Hager City, Sec. 35 T.25N. R.18W. In these vugs the quartz is often coated with calcite (W. S. Cordua field notes, 1992). Quartz also occurs as chert, banded chert and drusy crystals in the Sweeney Quarry, NW SW sec. 6 T. 27N. R.15W. west of Spring Valley on 250th Street.
—Quartz sand was mined by the Bay City Silica Company from the Jordan Formation approximately 1 mile E of Bay City (NW SW Sec. 3 T24N R17W). The workings are extensive with over 12 miles of tunnels up to 30 feet high (Crowns, 1976). Another large underground quartz sand mined is worked by Wisconsin Fract Sand in Maiden Rock. (W. S. Cordua field notes).
POLK COUNTY: Quartz crystals up to 15 cm long occur in quartz veins in the Dresser Trap Rock Quarry, Sec. 5 and 6 T35N R18W. Associated minerals include calcite, chlorite, epidote, cuprite, and malachite (Cordua, 1989b).
— Quartz occurs in amygdules in metabasalt as white crystals, blue masses and agate fillings and rinds in a small borrow pit east of Frederick (SE SE sec. 7 T.37N. R.16W.)
PORTAGE COUNTY: Quartz cemented sandstone with iron oxide mottling known as “zebra sandstone” is found in pits in SE SE Sec. 31 T23N R8E SW of Bancroft (WGNHS files).
RUSK COUNTY: Quartz as massive to vuggy blocks in gossan and as bluish “eyes” in schist occur at the Flambeau Mine south of Ladysmith (May, 1977).
—Quartz is the major component of the Barron quartzite. Good exposures are in Grundy Canyon (N half of Sec. 30 T.35N. R.9W.) and along Dejung Road (NW NW Sec. 18 T.36N. R .9W.) (W. S. Cordua field notes).
ST. CROIX COUNTY: Quartz as “Lake Superior agates” are widespread throughout the county. Gravel pits near New Richmond, Roberts and Hudson and gravel bars along the Apple and St. Croix Rivers are good places to search (Eckert, 1980; W. S. Cordua field notes).
—Small vugs in Prairie du Chien Group dolostones containing drusy quartz and calcite occur at the Beyer Quarry near Hudson (SE Sec. 7 T28N R19W) (Middleton and Williams, 1989).
—Quartz crystals, on banded agate rinds occur in vugs in Prairie du Chien Group rocks in the quarry on Tower Road near Hudson (NE Sec. 6 T27N R19W) (W. S. Cordua field notes).
—Quartz crystals several inches long occurred in vugs in Prairie du Chien dolostone exposed in the roadcuts along Hanley Raod, south edge of Hudson. These fluoresced a pale orange-yell0w under shortwave ultraviolet light (Cordua, 1998).
—Drusy crystals and coarsely banded agate nodules are found in Prairie du Chien Group dolostones in the quarry south of I94 near Woodville (W. S. Cordua field notes).
SAUK COUNTY: Quartz is the major component of the Baraboo Quartzite exposed widely throughout the region. Some of the better exposures are: lower Narrows of the Baraboo River east of Baraboo (S 1/2 of Sec. 23 T12N R7E); the buffs around Devil’s Lake (Sec. 23-26 T11N R6E).
—The LaRue Quarry (NW Sec. 22 T11N R5E), and the roadcuts along Hwy 12 S of Baraboo (NW Sec. 15 T11N R6E). Structures in these outcrops are world famous and are studied each year by hundreds of geology students. For this reason, NO HAMMERING OR SAMPLING should be done on any of them (Dalziel and Dott, 1970).
—Elongated needle-like crystals of quartz up to a centimeter long form a stockwork in a breccia zone in the Baraboo Quartzite expose in a quarry on the west side of the Rock Springs Narrows in the SE Sec. 29 T12N R5E. The quartz is associated with the clay mineral dickite (Dalziel and Dott, 1970). Quartz crystals with an average length of 3-6 mm found in the Devil’s Lake area were described in detail by Hobbs (1895) who noted the presence of many rare forms modifying the common habit of prisms with rhombohedral terminations.
—Quartz crystals occur in vugs along a brecciated zone within the Baraboo Quartzite exposed in the Martin Marietta Rock Springs Quarry (Brown et al., 2001).
SAWYER COUNTY: Quartz is the major component of the Barron Quartzite, as exposed in numerous places in Sawyer County. Some notable outcrops are east of Meteor (Sec. 10 and 11 T.37N. R.8W.), along a gorge near Couderay (Sec. 16 and 17 T.38N. R.8W) and along Sucker Creek (Sec. 35 and 36 T.37N. R.9W.). (Hotchkiss, 1915).
SHAWANO COUNTY: Quartz crystals occur in the complex pegmatite exposed in the Tigerton Dells in the NE SW NE Sec. 15 T.26N. R.12E.. Associated minerals include albite, K feldspar, bertrandite, beryl and phenakite (WGNHS files, 1986).
SHEBOYGAN COUNTY: Quartz as “Lake Superior agate” occurs in gravel pits near Cascade (Eckert, 1980).
TREMPEALEAU COUNTY: Quartz as “Lake Superior agate” occurs in gravel pits and gravel bars throughout the county (Eckert, 1980).
—Quartz of a pale amethyst shade is reported near Whitehall (Eckert, 1980).
WASHBURN COUNTY: Quartz as “Lake Superior agate” is found in gravel pits in the Spooner area (Eckert, 1980). Quartz crystals up to 1 cm long occur in fissures in basalt with epidote in Sec. 13 T.42N. R.10W. near Chittamo (Strong, 1880).
WINNEBAGO COUNTY: Drusy quartz crystals occur in vugs in Prairie du Chien Group dolostones near Eureka (Chamberlain, 1877).
—Drusy white, yellow and brown quartz crystals with attractive iridescent coatings occur in vugs in Prairie du Chien dolostones at the Allan Quarry east of Omro (NE SW Sec. 9 T.18N. R.14E. Associated minerals are drusy dolomite and coarse white calcite. (W. S. Cordua field notes, 1993).
WOOD COUNTY: Green (aventurine) and plum colored quartz found as a component of quartzite in quarries near Veedum about 5 miles SE of Pittsville along County E (S 1/2 Sec. 7 and N 1/2 Sec. 18 T22N R3E). The green coloration is due to the presence of chromium-rich muscovite, fuchsite (Greenberg et al., 1986).
—Red and yellow quartz forms chert at Power’s Bluff, (SE Sec. 30 T.24N. R.4E.) (Greenberg et al., 1986). Rockhounds use this material for cabochons.
—Crystals up to 2 cm long occur in veins with chlorite and anatase at the Tork and Haessley Company Quarries, Wisconsin Rapids (T. Buchholz,1996).
—Rose quartz is reported from near Grand Rapids (Schlegel, 1957)
—Quartz occurs are crystals in veins and xenoliths in granite in the quarry on the east side of County B, sec. 25 T.24N. R.2E. (Buccholz, personal communication, 1994).
—Occurs as excellent micrographic intergrowths with K feldspar in the granite of the Haske Quarry, (SW SE sec. 25 T.24N. R.2E.). It is also found as small xls. in vugs. (Buchholz et al., 1998)
—Occurs as float of granular pale rose masses west of Wisconsin Rapids, along the border of sect 10 and 11 T. 22N. R. 5E south of Hwy 13-73 (T. Buchholz, personal communication).