Rock Studies GEOL 75 – Rock and Minerals Minerals Quartz Calcite Plagioclase (Feldspar) Orthoclase (Feldspar) Biotite Muscovite Hornblende (Amphibole) Pyroxene Talc Chlorite Gypsum Olivine Halite (Common salt) Magnetite Hematite Chalcopyrite Pyrite Galena Sphalerite Barite Graphite Serpentine Pyrrhotite Rocks Nepheline Syenite Porphyry Gabbro Diorite Andesite Shale Gneiss Limestone (Fossiliferous) Rhyolite Basalt Granite Marble Banded Iron Formation (Taconite) Slate Muscovite Schist Limestone Dolomite Sandstone Talc Schist