mud - soil with mud, muck, or mire; The child mucked up his shirt while playing ball in the garden muck up, muck, mire begrime, bemire, colly, dirty, grime, soil - make soiled, filthy, or dirty; don't soil your clothes when you play outside!
Quartz is one of the most common minerals in the Earth's crust. It is made up of silicon dioxide (SiO2), otherwise known as silica. White sand is primarily made from quartz. Click here to find out more.
Silicon is the second most abundant element. Silicon dioxide and silicates (salts derived from silicon dioxide) make up about 87 percent of the materials in the Earth's crust. (Source: Tzimopoulos, Nicholas D., et al. Modern Chemistry, pp. 289, 758.) However water is the most common substance on the surface of the Earth. In the atmosphere, Nitrogen is the most common element (78%). It is believed that the core of our planet is mostly made of iron (at very high pressure and density), so iron would be the most common element within the Earth.