Allanite

Dark brown allanite-(Ce) grain, indicated by red arrow in granite. The allanite grain is about 5 mm in length. Specimen from the county quarry on Cary Mound in Wood County, Wisconsin. Collected by Tom Buchholz. (Image by W.S. Cordua.)

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 is often associated with epidote, biotite, zircon, monazite and a number of rare earth, uranium or thorium-bearing minerals.

ASHLAND COUNTY: Allanite is noted as an accessory in granite exposed along RR tracks along Bad River, 4 km north of Cayuga (Sims et al., 1985).

CLARK COUNTY: Allanite is a component of the Neillsville augen gneiss as exposed south of Neillsville in the NW 1/4 NW 1/4 Sec. 26 T.24N. R.2W along the Black River (Maas and Van Schmus, 1981).

FLORENCE COUNTY: Allanite is an accessory in the Hoskin Lake Granite, such as exposed in RR cut SW SE Sec.7 T.38N. R.20 E. (Sims et al., 1992)

MARATHON COUNTY: Metamict allanite is a common accessory in the Nine Mile granite widely quarried south of Wausau (Mursky et al., 1989). It is found as an accessory of the syenites of the Wausau and Stettin pluton west and south of Wausau. (Weidman,1907). Sood, Myers, Berlin (1980) note that allanite is particularly common in pegmatitic nepheline syenites such as at SE SE Sec. 22 T.29N R.6E.
—Component of the fayalite-bearing quartz syenite pluton at the Old Technical Institute in Wausau, NE NE Sec. 35 T.29N. R.7E. (LaBerge and Myers, 1983).
—Masses, weighing up to 2 lb. of yellow-brown weathering black, metamict allanite is found in soil at S1/2 NW Sec. 15 T 29N R6E. in an area of anomalous radioactivity (Vickers, 1956).
—Allanite-Ce has been found at the Red Rock Granite North pit, several miles southwest of rib Mountain along Spring Brook Road. It is also found at the Koss Pit, SW sec. 2 T.27N. R.5E. (Buchholz and Simmons, 2002)

MARINETTE COUNTY: Allanite is an accessory in the Haskins Lake granite near Niagara. Good exposures occur in the S1/2 Sec. 12 and N1/2 Sec. 13 T.38N R19E and NE Sec. 17 T.38N. R20E. (Prinz, 1965).
—Allanite is an accessory in the Dunbar Gneiss at numerous localities within the county. Some outcrops are in the SW SW sec. 21 T.37N. R.18E. and in roadcuts along County UU in the NW NW sec. 13 and NW NW sec. 14 T.37N. R.18E. (Sims et al., 1992)

OCONTO COUNTY: Allanite occurs as tiny altered grains in gneisses, granodiorite and other rocks in the Mountain area. (Sims et al., 1991)

PORTAGE COUNTY: Allanite is an accessory in the Red River Adamellite such as exposed in a pit near the center of Sec. 18 T.24N R8E north of Stevens Point (Greenberg et al., 1989).

SHAWANO COUNTY: Platy crystals up to 1/2 cm. across are found in the complex pegmatite south of the Tigerton Dells at NE SW NE Sec. 15 T.26N R.12E have been tentatively identified as allanite. Associated minerals are beryl, gadolinite, K-feldspar and chlorite. (WGNHS files, 1986).

WAUPACA COUNTY: Allanite is an accessory in the Waupaca adanellites as exposed in the granite quarry north of Waupaca in NW NW Sec. 4 T.22N R12E (Greenberg et al., 1989).
—Allanite is an accessory in the Red River Adamellite such as exposed along the Little Rib River S of Big Falls SE SE Sec. 26 T25N R12E (Greenberg et al., 1989).
—Allanite occurs in road cuts in pegmatite cutting granite along County G near Keller Lake, NE of Big Falls. Associated minerals include euxenite-(Y), biotite, fluorite, K feldspar, bastnaesite group minerals, and various sulfides. (Tom Buchholz, 2002, personal communication.)

WOOD COUNTY: Allanite is an accessory in the granite exposed in the Haske quarry in Sec. 25 T.24N. R.2E (Tom Buchholz, personal communication).
—Allanite was tentatively identified as associated with thorite in granite in the County Quarry, in Cary township (NW sec. 1 T. 23N R.2E). (Buchholz, personal communication, 2002).