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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 Carmelita Property is underlain by mid - Cretaceous rocks of the Cerrillos Formation of the Bandurrias Group, comprised mainly andesites, andesite agglomerates and porphyritic andesites with intrusive stocks.
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.
The dike cuts the older andesites in the northeastern and central parts of the district and flat-lying rhyolite ash-flow tuffs in the southwestern areas.
There is also the possibility that large-tonnage, bulk-mineable lower-grade epithermal gold mineralisation could occur in a favourable tuff horizon proximal to the silica-clay veins, that are hosted by more competent overlying andesites.
Year-2004 composite grab sampling of fault gouge and strongly silicified, carbonate-altered andesites returned values of 855 ppb Au, 0.
These trenches encountered altered and locally silicified andesites with broad zones of massive, low angle quartz veining, crosscut by high angle narrow veins.
This valley hosts two large satellite image anomalies which are largely coincident with felsic volcanics and intrusives that occur within a larger area of basalts and andesites.
Six distinctly different alteration zones form an approximately 200 meter thick vertical section across the exposed Miocene volcanics, with the mineralization located in pyroclastic andesites.