Published on Sep. 26, 2025, 8:24 PM
Science is a step closer to discovering the source of iron oxide found on the Moon.
Hematite, a form of iron oxide similar to rust, has been found on the Moon, and until now, the source was a confounding mystery.
When scientists examined the data returned by India’s first lunar orbiter, Chandrayaan-1, they found something very unexpected. There was hematite on the Moon’s surface.
A sample of hematite from Brazil is shown here next to the chemical formula and structure of the iron oxide molecules it is composed of. (Houston Museum of Natural Science/Scott Sutherland)
Hematite is a mineral form of iron oxide, the same substance as rust. Both are produced when iron is exposed to water and oxygen. The only difference between them, really, is that the iron oxide molecules in hematite are arranged in an orderly crystalline lattice, whereas the same iron oxide found in the reddish flakes peeling off of an exposed iron fence post, for example, are far more disorderly.
There’s a problem with finding hematite on the Moon, though.
We’ve known about water on the Moon for some time now. The permanently shadowed craters at the lunar south pole potentially have vast stores of it, locked away as ice. This water could be released into the environment, temporarily, due to dust particles and micrometeorites striking the surface.
These highlighted craters at the Moon’s south pole are in permanent darkness, which has allowed water to collect in them over millions to billions of years. (NASA)
READ MORE: NASA has its first detailed map of water on the Moon
However, the Moon’s thin atmosphere contains no oxygen. So, how did the hematite form?