Diopside is a rock-forming pyroxene mineral with a chemical composition of MgCaSi2O6. It occurs in igneous and metamorphic rocks at many locations around the world. Gem-quality crystals of diopside are faceted into attractive gemstones that are occasionally seen in commercial jewelery. Granular diopside can be easily cut and polished. When it has an attractive color, it is sometimes used as an ornamental stone. Perhaps the most important use of diopside is its value as an indicator mineral in the search for diamonds. Trail-to-lode prospecting using diopside and other indicator minerals has found diamond deposits in Canada, the United States, Africa, and other locations. Diopside has potential uses in the glass and ceramics industries, but the mineral usually occurs in accumulations that are too small or impure for effective mining - ""