The hematite, in conjunction with other iron oxides, replace iron carbonates. R.4E SE of Darlington. Here it occurs as interstitial material in the St. Peter Sandstone. 30 and NW NW Sec. Microscopic euhedral hexagonal prisms of hematite occur intergrown in microcline mircoperthite in the granitic rocks of the Ninemile Pluton.
Some good outcrops are in Sec.
T.28N R.7E and Sec. NE SW SW Sec. Several small iron mines were developed in hematite-rich compact red clays near Richland Center in SW Sec. 7 and SE Sec. A similar deposit was mined near Boaz in the NW Sec.