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Diorite is a grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar (typically andesine ), hornblende, and/or pyroxene. Varieties deficient in hornblende and other dark minerals are called leucodiorite. It is often described as "salt and pepper" when composed largely of light colored mineral randomly interspersed with dark minerals. When olivine and more iron rich augite are present the rock grades into ferrodiorite which is transitional to gabbro. The presence of quartz makes the rock type quartz diorite or tonalite and if orthoclase (potassium feldspar) is present the rock type grades into granodiorite .Diorites may be associated with either granite or gabbro intrusions, into which they may subtly merge. Diorite results from partial melting of a mafic rock above a subduction zone. It is commonly produced in volcanic arcs, and in cordilleran mountain building (subduction along the edge of a continent, such as with the Andes Mountains). It appears in thousands of sqare miles of large batholiths (mass of intrusive igneous rock believed to have solidified deep within the earth). The extrusive volcanic equivalent is andesiteAndesite is an igneous, volcanic ( extrusive) rock, of intermediate composition, with aphanitic to porphyritic texture. Mineral assembly is usually quartz and plagioclase. Biotite, hornblende and pyroxene are common accessory minerals. Alkali feldspar is.
Diorite is a relatively rare rock; source localities include SondrioSondrio Province is one of the 11 provinces of Lombardy in Italy, and the least populated. Sondrio town counts 21,642 inhabitants (2001) and is located in the northern part of Lombardy just in the very centre of Valtellina. The province covers 3,212 sq., ItalyThe Italian Republic or Italy ( Italian: Italia is a country in the south of Europe, consisting mainly of a boot-shaped peninsula together with two large islands in the Mediterranean Sea: Sicily and Sardinia. To the north, where it borders France, Switzer; ThuringiaState Service Flag Civil Flag Statistics Capital: Erfurt Area:16,171 kmē Inhabitants:2 392 000 2003 pop. density:148 people/kmē Homepage: ISO 3166-2:DE-TH Politics Minister-President: Dieter Althaus ( CDU) Ruling party: CDU Map The Free State of Thuringia and Sassonia in GermanyThe Federal Republic of Germany ( German: Bundesrepublik Deutschland is one of the world's leading industrialized countries, located in the middle of the European Union. It is bordered to the north by the North Sea, Denmark and the Baltic Sea, to the east; FinlandSuomen TasavaltaRepubliken Finland ( In Detail) ( In Detail) National motto: None Official languages Finnish and Swedish Capital Helsinki President Tarja Halonen Prime minister Matti Vanhanen Area Total % water Ranked 64th 337,030 kmē 9. 4% Population Tot; RomaniaRomania (formerly spelled Rumania or Roumania is a country in southeastern Europe. Romania is bordered by Ukraine and Moldova in the northeast, Hungary and Serbia in the west and Bulgaria to the south. Romania also has a small sea coast on the Black Sea.; central Sweden; Scotland; the Andes Mountains; and the Basin and Range province and Minnesota in the USA.
An orbicular variety found in Corsica is called corsite.
See also: list of rocks
Science stubs
Igneous rocks
