Large biotite crystals up to 12 cm. These can occassionly be found exposed in the granite quarries in Sec. R7E south of Rib Mountain. Large flakes of biotite altering to chlorite and containing tiny zircon inclusions occurs in the Newingham tonalite such as is exposed on the north side of U.S. Hwy. 5 T36N R20E and NW NW Sec.2 T36N R19E and a rail road cut in NW NW Sec.
Associated minerals are prochlorite, hornblnde and plagioclase.
Some outcrops are found at NW sec. 22, SW sec. 15, and along the railroad tracks in NE sec. Biotite is found with chloritoid, actinolite and stilpnomelane in the volcanic rocks in the wall rock altering zone of the Pelican River massive sulfide deposit in Sec. Biotite is common in the gneisses and tonalites exposed at numerous points in T.23N. R.7E. near Steven's Point.