Basalt
Hard, dark igneous rock, composed of 45 to 54 percent silica (SiO2) and often rich in iron and magnesium. Basalt is the most common type of rock in the crusts of many terrestrial worlds (especially Selenian, Arean, Venusian, and Gaian worlds.
 
Appears in Topics
Geology
 
Development Notes
Text by M. Alan Kazlev

Initially published on 08 October 2001.