Chemical analysis of the Genesis Rock indicated it is an anorthosite, composed mostly of a type of plagioclasefeldspar known as anorthite. The rock was formed in the early stages of the Solar System, at least 4 billion years ago.[2]
It was originally thought they had found a piece of the Moon's primordial crust, but later analysis initially showed that the rock was only 4.1 ± 0.1 billion years old, which is younger than the Moon itself, and was formed after the Moon's crust had already solidified. Research has shown that the Genesis Rock is not the oldest sample recovered from the moon, with sample 14321 (retrieved during the Apollo 14 mission) surpassing it.[3] It is still an extremely old sample, formed during the Pre-Nectarianperiod of the Moon's history. Dating of pyroxenes from other lunar anorthosite samples gave a samarium–neodymium age of crystallization of 4.46 billion years.[4] Other research methods approximate the age of the rock to be between 4 and 5 billion years old.[5]
↑Norman, M. D., Borg, L. E., Nyquist, L. E., and Bogard, D. D. (2003) Chronology, geochemistry, and petrology of a ferroan noritic anorthosite clast from Descartes breccia 67215: Clues to the age, origin, structure, and impact history of the lunar crust, Meteoritics and Planetary Science, vol 38, p. 645-661 Summary
