Fine Grained, Gray-Black Basalt Volcanic Rock - 10 Pieces
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Fine Grained Gray-Black Basalt Rock, 10 Pieces
by American Educational Products
An igneous, or volcanic, rock that formed due to the rapid cooling of lava that has been exposed to the open air or near the surface, it features a glassy matrix that is interspersed with minerals. Usually grey to black in color, it is known to weather rapidly to a brown or red because of the oxidization of the iron-rich minerals that are contained within it.
It is typically defined by both its mineral content, and texture. The fine grained variety of basalt is due to the molten rock cooling at an extremely high pace, which prevents mineral crystals from growing too large.