BASALT

Basalt

Basalt is a common extrusive igneous rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. By definition, basalt is an aphanitic igneous rock with less than 20% quartz and less than 10% feldspathoid by volume, and where at least 65% of the feldspar is in the form of plagioclase. Basalt is usually grey to black in colour, but rapidly weathers to brown or rust-red due to oxidation of its mafic minerals into rust. It almost always has a fine-grained mineral texture due to the molten rock cooling too quickly for large mineral crystals to grow, although it can sometimes be porphyritic, containing the larger ...

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basalt

Noun

  1. A hard mafic igneous rock of varied mineral content; volcanic in origin, it makes up much of the Earth's oceanic crust.
  2. A type of unglazed pottery.


The above text is a snippet from Wiktionary: basalt
and as such is available under the Creative Commons Attribution/Share-Alike License.

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