CI chondrite

CI chondrites, also called C1 chondrites or Ivuna-type carbonaceous chondrites, are a group of rare carbonaceous chondrites, a type of stony meteorite. They are named after the Ivuna meteorite, the type specimen. They represent the most chemically primitive meteorites known, with elemental compositions closely matching our Sun.

These rare carbonaceous chondrites are defined by their lack of visible chondrules due to extensive aqueous alteration. Despite this alteration, they preserved the solar system's original elemental composition, making them the standard reference material for cosmic abundances in planetary science. The Orgueil, Alais, Ivuna, Tonk, and Revelstoke meteorites, along with CI-like Antarctic specimens, provide windows into the early solar system's chemistry, the formation of volatiles, and possibly the origins of life's building blocks.