Geography
Answer
Igneous rocks are classified into two types on the basis of their chemical composition-
Acid Igneous rocks — These rocks have silica content between 65% to 85 %. They lack in iron and magnesium. For example- granite.
Basic Igneous Rocks — These rocks have higher percentage of oxides of denser elements and silica content varies between 40% to 60%. These are heavy and dark in colour. For example, Basalt.
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