Crust (geology) depth, reaching values typically in the range from about to at the boundary with the underlying mantle. The temperature increases by as much as for every kilometer locally in the upper part of the crust, but the geothermal gradient is smaller in deeper crust. The continental crust has an average composition similar to that of andesite. The most abundant minerals in Earth's continental crust are feldspars, which make up about 41% of the crust by weight, followed by quartz at 12%, and pyroxenes at 11%. Continental crust is enriched in incompatible elements compared to the basaltic ocean crust and much
Primary minerals of parent rocks. There are almost 3000 known minerals, but only 20 are common and just 10 minerals make up 90 % of the earth's crust. Primary minerals are defined as minerals found in soil but not formed in soil. This definition is different from that of secondary minerals, which are defined as minerals formed in soils." This is further defined by Dr. Broome of North Carolina State: Two types of minerals are found in natural systems: primary and secondary. Primary rocks are the source of primary minerals and primary water. Primary minerals A primary mineral is any mineral formed