An interesting link in the article explains the composition of our (Earth's) Moon:<p><a href="https://www.smithsonianmag.com/smart-news/our-moon-was-likely-covered-in-a-magma-ocean-long-ago-and-new-data-from-indias-lunar-rover-supports-that-theory-180984963/" rel="nofollow">https://www.smithsonianmag.com/smart-news/our-moon-was-likel...</a><p>""Indian astronomers analyzed data on the 23 regolith samples studied by the APXS to understand the soil’s mineral composition. These were the first soil composition measurements ever registered from near the moon’s south pole, and the scientists found that all of them included ferroan anorthosite, a type of white rock.<p>""That finding supports the idea that the moon was once enveloped by magma. “A key prediction of the lunar magma ocean hypothesis is the presence of a largely anorthositic crust,” Vadawale tells Popular Science’s Tom Hawking. This is because during the moon’s magma ocean phase, dense rocks—like magnesium-rich mafic rocks—would have sunk inward, while lighter rocks—like ferroan anorthosite—would have floated to the top."