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Title
Rock #120118370
Description
RockÃâàorÃâàstoneÃâàis a natural substance, a solidÃâàaggregateÃâàof one or moreÃâàmineralsÃâàorÃâàmineraloids. For example,Ãâàgranite, a common rock, is a combination of the mineralsÃâàquartz,ÃâàfeldsparÃâàandÃâàbiotite. The Earth& x27;s outer solid layer, theÃâàlithosphere, is made of rock. Rock has been used by humankind throughout history. The minerals and metals in rocks have been essential to human civilization.