The first stage of naming an igneous rock is determining whether it is phaneritic or aphanitic. The next step involves the determination of its mineral constituents. The chemical composition of magma is closely related to how explosive and hazardous a volcanic eruption will be. The variation in the amount of silica (Si02) in igneous rocks is used to describe the variation in composition of igneous rocks and the magmas that formed them, as shown in the table "Names of Igneous Rocks Based on Silica Content and Texture." Rocks with low amounts of silica (basalt, gabbro) are known as mafic rocks, whereas rocks with high concentrations of silica (rhyolite, granite) are silicic or felsic rocks.
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Disasters: Why No ones Really 100 Safe. This is common knowledgethat disaster is everywhere. Its in the streets, its inside your campuses, and it can even be found inside your home. The question is not whether we are safe because no one is really THAT secure anymore but whether we can do something to lessen the odds of ever becoming a victim.