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rhyoliteColumbia Encyclopedia entry: rhyolite
Rhyolite, fine-grained light-colored acidic volcanic rock. Rhyolite is chemically the equivalent of granite, and is thus composed primarily of quartz and orthoclase feldspar with subordinate amounts of plagioclase feldspar, biotite mica, amphiboles, and pyroxenes. Rhyolite lava exhibits a typical banded structure produced by its flow pattern. Rhyolite lavas occur in continental and submarine volcanoes, especially island arcs, and in igneous dikes. Rhyolite lavas are typically highly viscous and are explosively ejected from volcanoes. Rhyolites were formed in profusion in the Yellowstone Park area and throughout the southwestern portion of the United States.
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Wikipedia search results for: Rhyolite
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This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.
Rhyolite is an igneous, volcanic rock, of felsic composition. It may have any texture from glassy to aphanitic to porphyritic. The mineral assemblage is usually quartz, alkali feldspar and plagioclase. Biotite and hornblende are common accessory minerals.
Rhyolite can be considered as the extrusive equivalent to the plutonic granite rock, and consequently, outcrops of rhyolite may bear a resemblance to granite. Due to their high content of silica and low iron and magnesium contents, rhyolite melts are highly polymerized...more »
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Topaz, aluminum silicate mineral with either hydroxyl radicals or fluorine, Al2SiO4(F,OH)2, used as a gem. It is commonly colorless or some shade of pale yellow to wine-yellow; pale blue and p...
