Graphene is embedded as individual flakes or formed as part of a carbon shell enclosing the mineral particles. The result reveals one typical structure of indigenous carbon in the Moon, and its formation mechanism has been proposed. This finding may reinvent the understanding of chemical components, geography episodes and the history of the Moon. The graphene is abundant near the metal-containing (including Fe) compound, as also described in the following core-shell structures.

Abundant carbon sources on the moon would be good for future development of the moon and solar systems. This would enable the creation of methane or other carbon based fuel. IF graphene was abundant then it could be good for using graphene to make products on the moon. Graphene is one of the strongest and lightest materials. IF graphene is formed on the moon in a more efficient process then we could learn how to make graphene more efficiently on earth.

The CE-5 lunar regolith was drilled at a depth of ~0.9 m in the northern Oceanus Procellarum at 51.8 degrees west longitude and 43.1 degrees north latitude on the lunar frontal surface on December 1, 2020, which has not been heavily affected by human interference. The sample was recently returned from the moon.

The identification of graphene in the core-shell structure suggests a bottom-up synthesis process rather than exfoliation, which generally involves a high-temperature catalytic reaction. Therefore, a formation mechanism of few-layer graphene and graphitic carbon is proposed here. Volcanic eruption, a typical high-temperature process, occurred on the Moon. Lunar soil can be stirred up by solar wind, and high-temperature plasma discharge can be generated on the Moon's surface. The Fe-bearing mineral particles, such as olivine and pyroxene, in lunar soil might catalyze the conversion of carbon-containing gas molecules in the solar wind or polycyclic aromatic hydrocarbons into graphitic carbon of different thicknesses and morphologies on their surfaces including few-layer graphene flakes and carbon shells. In short, the formation of graphitic carbon may be attributed to high-temperature processes resulting from volcanic eruptions. Importantly, this mechanism suggests the presence of a carbon-capture process on the Moon, which might lead to the gradual accumulation of indigenous carbon. Since the discovery of graphene in meteorites or on the moon is extremely rare, impact processes from meteorites, which create high-temperature and high-pressure environments, may also lead to the formation of few-layer graphene and