enstatite

/ˈɛnstəˌtaɪt/
noun
  1. A common mineral, a type of pyroxene, usually grayish or greenish, found in igneous and metamorphic rocks.
    • The meteorite contained crystals of enstatite, indicating its origin in space.
    • Geologists found enstatite in the rock samples collected from the volcano.
    • Enstatite is often used in jewelry as a gemstone, though it is not very hard.