Hornblende andesite porphyry is an intermediate volcanic igneous rock. Like most porphyrys, it cooled at two separate rates, causing two sizes of crystals to be visible.
Source: [http://osdir.com/ml/culture.stone/2006-02/msg00238.html]
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Andesite — For the extinct cephalopod genus, see Andesites. Andesite (pronEng|ˈændəsaɪt) is an igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. The mineral assemblage is typically dominated by plagioclase plus… … Wikipedia
Mines and Geosciences Bureau Region 13 (Philippines) — DENR Mines and Geosciences Bureau Region 13 Kawanihan ng Pagmimina at Agham Panlupa Bureau/Regional overview Headquarters DENR MGB Compound, Km. 2 National Highway, Surgao City Annual budget Personal Services P25.14 million (2011) Bureau/Regional … Wikipedia
Geology of Jersey — The geology of Jersey is characterised by the Late Proterozoic Brioverian volcanics, the Cadomian Orogeny, and only small signs of later deposits from the Cambrian and Quaternary periods. The kind of rocks go from conglomerate to shale, volcanic … Wikipedia
Superior craton — in the west. The western margin extends from northern Minnesota through eastern Manitoba to northwestern Ontario.The formation of the Superior craton is best explained within the context of 2.72 2.68 Ga accretion of small continental plates and… … Wikipedia
Geology of Tasmania — Tasmania has a varied geological history, with the world s biggest exposure of diabase, or dolerite. Rocks from the Neoproterozoic, Paleozoic and Mesozoic time periods appear. It is one of the few southern hemisphere areas glaciated during the… … Wikipedia
Diorite — classification on QAPF diagram Di … Wikipedia
Geology of the Australian Capital Territory — Australia grew around three fused pieces of very ancient continental crust (cratons). The geology of the Australian Capital Territory includes rocks dating from the Ordovician around 480 million years ago, whilst most rocks are from the Silurian … Wikipedia
Metamorphic rock — Metamorphic redirects here. For other uses, see Metamorphic (disambiguation). Quartzite, a form of metamorphic rock, from the Museum of Geology at University of Tartu collection. Metamorphic rock is the transformation of an existing rock type,… … Wikipedia
Mine troïlus — Sommaire 1 Localisation 2 Géologie régionale 2.1 Généralités 2.2 Stratigraphie 2.3 … Wikipédia en Français
Mine Troïlus — Pour les articles homonymes, voir Troïlus (homonymie). La mine Troïlus est une mine de cuivre et d or à ciel ouvert du nord du Québec, située à 120 kilomètres au nord de Chibougamau. Elle est exploitée par la compagnie minière Inmet Corp.… … Wikipédia en Français
