Igneous
81Colorado Plateau — A map of the Colorado Plateau. The …
82Clastic rock — A thin section of a clast (sand grain), derived from a basalt score. Vesicles (air bubbles) can be seen throughout the clast. Plane light above, cross polarized light below. Scale box is 0.25 mm Clastic rocks are composed of fragments, or clasts …
83pyroxene — pyroxenic /puy rok sen ik/, adj. /puy rok seen, peuh , puy rok seen /, n. any of a very common group of minerals of many varieties, silicates of magnesium, iron, calcium, and other elements, occurring as important constituents of many kinds of… …
84Circum-Superior Belt — Map of cratons, orogenies and the Circum Superior Belt. Areas associated with the Circum Superior Belt include …
85Granite — For other uses, see Granite (disambiguation). Granite Igneous Rock Granite containing potassium feldspar, plagioclase feldspar, quartz, and biotite and/or amphibole Composi …
86Metamorphic rock — Metamorphic redirects here. For other uses, see Metamorphic (disambiguation). Quartzite, a form of metamorphic rock, from the Museum of Geology at University of Tartu collection. Metamorphic rock is the transformation of an existing rock type,… …
87Phlogopite — Phlogopite, Monte Somma, Italy General Category Mica, phyllosilicates …
88Lamprophyre — Lamprophyres (Greek λαµπρός (lamprós) = bright and φύρω (phýro) = to mix) are uncommon, small volume ultrapotassic igneous rocks primarily occurring as dikes, lopoliths, laccoliths, stocks and small intrusions. They are alkaline silica… …
89feldspar — /feld spahr , fel /, n. any of a group of minerals, principally aluminosilicates of potassium, sodium, and calcium, characterized by two cleavages at nearly right angles: one of the most important constituents of igneous rocks. Also, felspar.… …
90feldspathoid — /feld spa thoyd , fel /, Mineral. adj. 1. Also, feldspathoidal. of or pertaining to a group of minerals similar in chemical composition to certain feldspars except for a lower silica content. n. 2. a mineral of this group, as nepheline. [1895… …
