Enstatite chondrite
Enstatite chondrites are highly reduced chondrites made mostly of the iron-poor pyroxene enstatite, formed in an oxygen-starved environment.
Enstatite chondrites formed where there was very little oxygen. As a result, almost all their iron is locked up as metal or sulfide, and their main silicate is enstatite, a magnesium-rich pyroxene containing almost no iron. They also host strange minerals that cannot survive in oxygen-rich conditions, such as oldhamite, a calcium sulfide, and silicon dissolved in their metal. Two groups are recognised: EH (high iron) and EL (low iron), with petrologic types from 3 to 6.
They matter because their oxygen isotopes, and those of several other elements, are almost identical to Earth's and the Moon's. Many researchers therefore think material resembling enstatite chondrites made up a large share of the building blocks of our planet. Abee, a 107-kilogram EH4 stone that fell in Alberta, Canada, on 9 June 1952, is a classic example, and Neuschwanstein, which fell on the German–Austrian border in 2002, is an EL6.
Enstatite chondrites are usually grey with abundant fine metal, so they are magnetic. Their unusual sulfides react with moisture, so specimens tarnish easily and must be stored very dry.
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