CI Carbonaceous Chondrites

CI Carbonaceous Chondrites are among the rarest and most chemically primitive meteorites known, representing some of the closest matches to the original composition of the solar nebula. The ‘CI’ designation comes from Ivuna, the type specimen of the group. Formed over 4.5 billion years ago, these meteorites have undergone extensive aqueous alteration on their parent body, meaning they interacted heavily with water early in their history. Despite this, they retain a bulk chemical composition that closely mirrors that of the Sun, excluding volatile gases.

CI Carbonaceous Chondrites are typically dark, fine-grained, and lack visible chondrules, setting them apart from most other Chondrite groups. They are rich in water-bearing minerals, organic compounds, and volatile elements, but contain very little metal. Their soft and fragile nature means they are rarely found in large or well-preserved specimens, and they are highly susceptible to terrestrial weathering.

Studying CI Carbonaceous Chondrites provides critical insight into the original building blocks of the solar system, including the role of water and organic material in planetary formation. They are of particular importance in understanding how Earth may have acquired its volatile elements. For collectors, CI Chondrites are extremely rare and scientifically significant, representing some of the most primitive and chemically informative material available.