Carbonaceous chondrites constitute a subcategory of chondrites – which in turn are stony meteorites. Carbonaceous chondrites are the most primitive meteorites identified thus far and are mostly regarded as remnants of the first solid bodies to accrete in the solar nebula. The main components of carbonaceous chondrites are chondrules and CAIs (Ca-Al-rich inclusions), which are embedded in a matrix of micrometer-sized dust particles. Since carbonaceous chondrites contain the highest concentration of volatile elements and molecules (e.g., organic refractory matter) of the chondrites, they are thought to have formed at the lowest temperatures. Their chemical composition is very similar to that of the Sun (albeit depleted in hydrogen and helium), and thus they can be considered (apart from comets) to be the most primitive material present in our solar system.