Scientists have made a surprise discovery in soil samples collected from the lunar surface that could help unravel the mystery behind the Moon’s magnetic anomalies.
The samples, retrieved by China’s Chang’e-6 mission in 2024, reveal the presence of minuscule iron rust samples, which researchers say could expand our current knowledge of the surface chemistry of Earth’s natural satellite.
According to a new paper in Science Advances, researchers studying the Chang’e-6 samples discovered two micrometer-scale iron oxide variants—crystalline hematite and maghemite—in the samples. This challenges past assumptions about the lunar surface, which have assumed that such an arid environment would prevent the formation of iron oxides.
Mounting Evidence for a Rusty Moon
The new findings, reported in the South China Morning Post, are not the first time that evidence of rust formation has been discovered on the Moon. In 2020, data from the Indian Space Research Organization’s (ISRO) Chandrayaan-1 orbiter’s Moon Mineralogy Mapper (M3) instrument, designed by NASA’s Jet Propulsion Lab, similarly revealed spectral data indicating the presence of hematite, which is normally produced through the process of iron’s exposure to oxygen and water.
Going further back, magnetite and iron hydroxides, which are also materials associated with ferric iron, were revealed in samples retrieved during NASA’s Apollo missions. However, researchers concluded during analysis in the early 1970s that the instability of such compounds while in the lunar environment likely meant that the presence of iron hydroxides had resulted from later contamination after the samples were returned to Earth.
Additional evidence of nanophase magnetite was identified in lunar regolith samples in 2022, which were obtained by China’s Chang’e-5 mission. With the newest data from the Chang’e-6 samples, scientists have now confirmed the mineral component to this mystery, revealing that the presence of hematite in the lunar soil appears to be a consistent element of the Moon’s geologic makeup.
Intense Heat and Pressure
Minerals that were found to contain iron rust during recent analysis were mainly breccias—samples consisting of angular fragments that undergo cementation when exposed to extreme heat and pressure, which is produced by meteors that have frequently impacted the lunar surface for eons.
By comparison, analysis of samples composed mainly of volcanic materials showed no signs of the minerals possessing oxidized iron. Based on this, the researchers behind the recent study suggest that extreme conditions associated with impact events like those believed to be responsible for the formation of the Moon’s South Pole-Aitken basin, where the samples were retrieved by the Chang’e-6 mission, are responsible for the presence of the hematite samples.
Solving the Moon’s Magnetic Mysteries
Significantly, the sudden heating minerals undergo during impact events likely play a crucial role in the release of oxygen, which, upon its release into the environment, interacts with other minerals that are rich in iron.
The researchers also argue in their study that the presence of such iron oxides, particularly in the form of maghemite, “may be the mineralogical reason for the generation of the magnetic anomalies observed around the South Pole–Aitken basin.”
With the confirmed discovery of hematite in lunar soil samples, researchers are now armed with important new information about the local environment and how it gives rise to reactions that have influenced the Moon’s chemistry and geological makeup over time, as well as its unique magnetic properties.
The team’s paper, “Discovery of crystalline Fe2O3 in returned lunar soils,” appeared in Science Advances on November 14, 2025.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
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