Formula: Ca2Al3(Si2O7)(SiO4)O(OH) Monoclinic
Description: Common in low-grade metamorphic rocks, particularly as an alteration product of plagioclase.
ASHLAND COUNTY: Formed as an alteration product of plagioclase in the gabbros near Mellen, where it forms with epidote, zoisite, calcite and chlorite. It is particularly common in outcrops in Sec. 20, 21 and 28-33 in T.45N R.4W (Leighton, 1954).
BAYFIELD COUNTY: Formed as an alteration product of plagioclase in Keweenawan gabbros throughout the county. It is particularly common in outcrops in Sec. 25, 35, and 36 in T.45N R.5W and in Sec. 1-9, 11-13 and 16-18 in T.44N R.5W (Leighton, 1954).
— Occurs in felsite porphyry in the SE SW Sec. T.44N R.6W (LaPoint, 1976).
FLORENCE COUNTY: Found as an accessory mineral in the Newingham granodiorite in outcrop on the north side of U.S. Hwy. 8 (center of the N 1/2 Sec. 5 T.36N R.20E) west of Pembine (Banks and Cain, 1969).
FOREST COUNTY: Found in metavolcanic rocks at the Crandon deposit near Little Sand Lake (Lambe and Rowe, 1989).
MARINETTE COUNTY: Clinozoisite occurs as an accessory in the Amberg granite in the large quarry near Middle Inlet in the NE Sec. 30 T.33N R.20E. It occurs with epidote and sericite as an alteration product of plagioclase (Banks and Cain, 1969).
OCONTO COUNTY: Clinozoisite occurs with epidote and chlorite in numerous outcrops of metavolcanic rock near Mountain. (Sims et al., 1991).
POLK COUNTY: Clniozoisite has been found as radiating crystals with epidote and quartz in amygdules in basalt exposed in a small borrow pit near Lewis, Wisconsin.