tonalite An oversaturated, coarsegrained, igneous rock consisting of essential sodic plagioclase (An27–36), quartz, hornblende, and/or biotite, with accessory apatite, zircon, and iron oxide.
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Magnetite , magnetite (loadstone, lodestone) An important rock-forming iron oxide Fe2+Fe3+2O4 (FeO.Fe2O3) and member of the spinel group of minerals; belongs to… Peridotite , peridotite A coarse-grained, ultrabasic, igneous rock consisting of essential magnesium-rich olivine accompanied by lesser amounts of other ferromagn… Trachyte , trachyte Fine-grained volcanic rock of the alkaline series of intermediate rocks. Trachyte is the volcanic equivalent of syenite. trachyte gritty vol… Mafic , Mafic Igneous rocks are classified by geologists using various schemes. One of the several schemes based on chemical composition divides igneous rock… Basic Rock , basic rock Rock with a relatively high concentration of iron, magnesium, and calcium, and with 45–53% of silica by weight. Examples include gabbro, w… Metasomatism , skarn •Abadan, Abidjan, Amman, Antoine, Arne, Aswan, Avon, Azerbaijan, Baltistan, Baluchistan, Bantustan, barn, Bhutan, Dagestan, darn, dewan, Farne,…
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