Part of the Faculty of Social Sciences at the University of Victoria, PACTAC is a pioneering, multidisciplinary research centre, and home to the electronic scholarly journal CTheory, CTheory Archive, and CTheory Multimedia.
Rocks: Rocks are a composed of one or more minerals. A rock can be made up of only one mineral or, as shown in the figure, a rock can be made up of a number of different minerals. So, rocks are composed of one or more minerals and minerals are composed of one or more elements. Previous Item: Why should we study rocks? Go Up: Learn About Rocks
Igneous Rocks. Igneous rocks form directly from magma inside the earth's crust (called: plutonic or intrusive) or lava on the earth's surface (volcanic or extrusive).Light-colored igneous rocks (pumice, rhyolite & granite) are composed of larger amounts of silica and are said to be felsic (feldspar + silica).gneous Rocks. Igneous rocks form directly from magma inside the earth's crust (called: plutonic or intrusive) or lava on the earth's surface (volcanic or extrusive).