Chemical composition and classification: Can be found in the fom of magnetite (Fe3O4, 72.4% Fe), hematite (Fe2O3, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe) or siderite (FeCO3, 48.2% Fe).
Properties: They can be fed directly into iron-making blast furnaces and are rich in oxides.
Location: Silver Bay, Minnesota
Uses: Used to make steel of various types.
Chemical composition and classification: An oxide of silicon with the chemical formula SiO2, most commonly found in nature as quartz.
Properties: Solid, crystallized mineral. Colorless.
Location: Southeastern Minnesota.
Uses: Electrical insulation in electronics, food industry, pharmaceutical industry.
Chemical composition and classification: Al2Si2O5(OH)4
Properties: Low shrink–swell capacity and a low cation-exchange capacity.
Location: Minnesota River Valley
Uses: Making bricks, coating for paper manufacturing, and pottery.
