To convey anything about the physical or chemical properties of the rock, a more specific term should be used; a good supplier will know what sort of volcanic rock they are selling.

Basalt - Wikipedia Basalt - Wikipedia

The sharp, angled texture makes ʻaʻā a strong radar reflector, and can easily be seen from an orbiting satellite (bright on Magellan pictures). Examples of continental flood basalts included the Deccan Traps in India, [85] the Chilcotin Group in British Columbia, [86] Canada, the Paraná Traps in Brazil, [87] the Siberian Traps in Russia, [88] the Karoo flood basalt province in South Africa, [89] and the Columbia River Plateau of Washington and Oregon. Volcanogenic massive sulfide occurrence model: Chapter C in Mineral deposit models for resource assessment".Textural criteria are less critical in classifying intrusive rocks where the majority of minerals will be visible to the naked eye or at least using a hand lens, magnifying glass or microscope. Temperatures can also exceed the solidus of a crustal rock in continental crust thickened by compression at a plate boundary. High-Ti and Low-Ti basalt has been distinguished in the Paraná and Etendeka traps [36] and the Emeishan Traps. Felsic magma, such as rhyolite, is usually erupted at low temperature and is up to 10,000 times as viscous as basalt. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses.

Lava - Wikipedia Lava - Wikipedia

Likewise, regular vertical patterns on the sides of columns, produced by cooling with periodic fracturing, are described as chisel marks.An aphanitic (fine-grained) igneous rock is classified as basalt when its QAPF fraction is composed of less than 10% feldspathoid and less than 20% quartz, with plagioclase making up at least 65% of its feldspar content. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Differentiation of most magmas tends to increase the silica ( SiO 2) content, mainly by crystal fractionation.