Trachyte: A light gray igneous rock with a rough surface consisting of orthoclase feldspar.
Translucent: Allowing light to pass through, but not transparent.
Trachyte...{trak'-yt}
Trachytes are volcanic rocks of intermediate silica and high alkali content.
Associations:
Produced by weathering or hydrothermal alteration of iron-bearing minerals. May be found in some syenite, trachyte, granite and rhyolite.
Industrial / ecomonic uses:
Important ore or iron, sometimes used as a gemstone.
Composed predominantly of basalt, several other volcanic rocks including trachyte and rhyolite are not uncommon.
Sanidine is common in rapidly cooled volcanic rocks, such as obsidian and felsic pyroclastic rocks. A notable locality with sanidine is in the trachytes of the Drachenfels, Germany. The lower-temperature polymorph of orthoclase is microcline.
masses, vitreous in luster, and breaking rather easily in two directions at right angles to each other. The feldspars are essential constituents of nearly all crystalline rocks, such as Granite, gneiss, mica, slate, most kinds of basalt and trachyte, ...
 See also: Mineral, Crystal, Crystals, Glass, Pink
  
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