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A gray, fine-grained volcanic rock consisting chiefly of plagioclase feldspar and one or more mafic minerals.

[After the Andes.]


(ˈændɪˌzaɪt) or


(Geological Science) a fine-grained tan or grey volcanic rock consisting of plagioclase feldspar, esp andesine, amphibole, and pyroxene
[C19: from Andes + -ite1]


(ˈæn dəˌzaɪt)

a dark volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals.
[1840–50; after the Andes; see -ite1]
an`de•sit′ic (-ˈzɪt ɪk) adj.


A dark, fine-grained rock, taking its name from the Andes Mountains.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.andesite - a dark grey volcanic rockandesite - a dark grey volcanic rock    
igneous rock - rock formed by the solidification of molten magma
References in periodicals archive ?
This mineralization takes place as breccia matrix fill, disseminations and veinlets in altered andesites.
Afyon Bolgesi Andezitlerine Seramik Sir Tekniklerinin Uygulanmasi ve Endustriyel Yeni Urun Gelistirme" (Implementation of Ceramic Glaze Techniques on Andesites of Afyon Region and Development of New Industrial Product), Afyonkarahisar: Turkey VI.
The dominant composition of these lava flows are porphyritic andesites, with subordinate basalts.
Petrological studies of lava flows show several varieties of andesites and dacites, which include hypersthene, hornblende, lamprobolite andesites and hornblende biotite dacite.
Like the Wagholi basalts, the Lonavala andesites contain a great number of cavities; however they have been uncovered in only a few areas at the bottom of the quarry.
The license area contains arc-magmatic rocks of Tertiary age, largely consisting of grano-dioritic intrusives and related porphyric andesites, typical of volcanic arc environments, where epithermal gold-silver mineralization can be expected.
During the Oligocene epoch an acid igneous intrusive of batholith size intruded the Jurassic sediments and the Eocene andesites throughout the Barrancas subprovince.
These sequences were subsequently intruded by 38 million year old (Eocene) magmas and overlain by Miocene basalts and andesites.