important constituent of some metamorphic rocks such as granulite. Orthopyroxene near pure enstatite in composition occurs in some metamorphosed serpentines. Large crystals, a foot in length and mostly altered to steatite, were found in 1874 in the apatite veins traversing mica-schist and hornblende-schist at the apatite mine of Kjørstad, near Brevik in southern Norway. Enstatite is a common mineral in meteorites. Crystals have been found in stony and iron meteorites, including one that fell at Breitenbach in the Ore Mountains, Bohemia. In some meteorites, together with olivine it forms the bulk of the material; it can occur in small spherical masses, or chondrules, with an internal radiated structure. Enstatite in space Enstatite is one of the few silicate minerals that have been observed in crystalline form outside the Solar System, particularly around evolved stars and planetary nebulae such as NGC 6302. Enstatite is thought to be one of the early stages for the formation of crystalline silicates in space. Many correlations have been noted between the occurrence of the mineral and the structure of the object around which it has been observed. Enstatite is thought to be a main component of the E-type asteroids. The Hungaria asteroids are the main examples in the Solar System. See also References Deer, W. A., Howie, R. A., and Zussman, J. (1992). An introduction to the rock-forming minerals (2nd ed.). Harlow: Longman Inosilicates Magnesium minerals Iron(II) minerals Pyroxene group Orthorhombic minerals Minerals in space group 61