Rocks and Minerals
Minerals are naturally occurring substances of inorganic origin that have a definite chemical composition and usually exhibit a crystalline structure. Plants and animals require a wide variety of minerals in order to survive on a daily basis. Minerals are also important, however, as the basic building blocks of rocks, which comprise the solid portion of the Earth and other planets. Rocks are formed through various means and are usually broadly categorized based on this fundamental characteristic. More precisely, igneous rocks are those that have solidified from magma, sedimentary rocks are those that have formed from fragments, or sediments, of other rocks, and metamorphic rocks are produced via the alteration of igneous or sedimentary rocks.
