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.
Of the 92 naturally occurring elements, the Earth's geosphere -- the solid part of the Earth made up of the core, the mantle and the crust -- is primarily composed of only four. These four are iron, oxygen, silicon and magnesium. These elements make up more than 90 percent of the Earth's mass. Tip The millions of substances in the earth are primarily made up of four elements: iron, magnesium, silicon and oxygen.