Minerals

Mineralogists group minerals according to the chemical elements they contain. Elements are substances that cannot be broken down into simpler substances through chemical means. Over 100 of these are known, of which 88 occur naturally. However, most occur only in extremely small traces. Only ten elements account for nearly 99% of the weight of Earth's crust. Oxygen is the most plentiful element, accounting for 49.2% of the weight of Earth's crust. Next is silicon, which accounts for 25.7% of its weight. Table 1 lists the 10 most abundant elements in Earth's crust. Most minerals are compounds; that is, they contain two or more elements.