Why are most rock-forming minerals silicates? Also, considering the composition of Earth's crust, do all of the non-silicate mineral groups make sense chemically? Why or why not?
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1. Why are most rock-forming minerals silicates?
Geologists classify rocks in three groups, according to the major Earth processes that formed them. The three rock groups are igneous, sedimentary, and metamorphic rocks. http://interactive2.usgs.gov/learningweb/explorer/topic_rocks.htm
Given the abundance of oxygen and silicon in the crust, it should not be surprising that the most abundant rock-forming minerals in the earth's crust are the silicates (which means that they are based on silica and oxygen for their basic elemental components). Although the Earth's material must have had the same composition as the Sun originally, the present composition of the Sun is quite different. These general element abundances are reflected in the composition of igneous rocks. http://hyperphysics.phy-astr.gsu.edu/hbase/tables/elabund.html
That is, the rock-forming minerals that are silicates form igneous rocks, which mean that the vast majority of rock-forming minerals are silicates because the earth's crust is made mostly of igneous rock - at least at the surface where our planet is exposed to the coldness of space. Igneous rocks are crystalline solids, which form directly from the cooling of magma. This is an exothermic process (it loses heat) and involves a phase change from the liquid to the solid state. Igneous rocks are given names based upon two things: composition (what they are made of) and texture (how big the crystals are). The silicates can be further divided into mafic and felsic - 2 very broad categories which relate to ...
This solution answers the following questions: Why are most rock-forming minerals silicates? Also, considering the composition of Earth's crust, do all of the non-silicate mineral groups make sense chemically? Why or why not?