Carbonaceous chondrite
A carbonaceous chondrite is a rare, usually dark chondrite that contains water-bearing minerals and carbon-rich compounds.
Carbonaceous chondrites are dark, often crumbly stony meteorites. Many contain carbon in the form of complex organic compounds, and many hold water locked inside clay-like minerals. They make up only a few per cent of meteorite falls, but they are among the most precious to science.
They are divided into groups named after a typical member, such as CI (for Ivuna), CM (Mighei), CV (Vigarano), CO (Ornans), CR (Renazzo) and CK (Karoonda). Some have chemical compositions very close to that of the Sun, apart from the lightest gases, so they are like samples of the raw material that built the planets. Others contain the oldest known solids. The Murchison meteorite, which fell in Victoria, Australia, on 28 September 1969, contains dozens of kinds of amino acids, building blocks of proteins, made without life in space. Samples brought back from the asteroids Ryugu and Bennu are similar to carbonaceous chondrites.
Carbonaceous chondrites are often black or dark grey inside, feel light for a stone, and can crumble easily. They must be kept dry and clean, so scientists handle fresh falls with gloves and store them carefully.
Related terms
Level: Explorer Ages 10 and up