Basalt

Basalt / noun :

First Page Mentioned (By Name) : ch. “Condemned Complex” – pg. 72

Basalt is the most common extrusive volcanic rock type on Earth, and it's formed when basaltic lava is exposed around the surface of a planet or moon, just to be rapidly cooled. Its composition is a finely grained and/or glassy matrix, containing between 45% and 53% silica, with less than 10% feldspathoid by volume, and at least 2/3rds of the rock is plagioclase formed fledspar. It tends to be grayish to black in color early on, but exposure to oxygen can cause its elements to rust, changing it to a reddish brown over time.

Where you find basalt, you are also likely to find other metamorphic and igneous rocks, such as scoria and pumice, all three of which Geb has plenty.

Related Entries: Earth; Geb (The Island Of); Igneous Rock; Metamorphic Rock; Pumice; Scoria

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