Ideal crystal structure of magnesiochangesite-(Y). Photo: Courtesy of Beijing Research Institute of Uranium Geology

Ideal crystal structure of changesite-(Ce). Photo: Courtesy of Chinese Academy of Geological Sciences

Chinese scientists have identified two previously unknown lunar minerals from the 1,731 grams of moon samples returned by Chang'e-5 mission, marking another major breakthrough in deep-space research. The findings were announced on Friday at the opening ceremony of the 11th China Space Day. The two newly discovered minerals have been officially approved and classified by the International Mineralogical Association. They are named magnesiochangesite-(Y) and changesite-(Ce).

This marks the second and third lunar minerals discovered by Chinese scientists, following the first discovery of changesite-(Y) in 2022. Globally, they are the seventh and eighth new lunar minerals identified in returned lunar samples.

The release of their ideal crystal structures drew strong reactions at the event. Though only a few micrometers in size, the crystals reveal the microscopic beauty hidden beneath the Moon's barren surface and reinforce the idea that the Moon is a vast and resource-rich body.

Global Times reporters learned that both minerals belong to the rare-earth phosphate category and are embedded within lunar dust. Their crystal structures are unique, with no exact counterparts found on Earth. They are part of the merrillite group, a class of phosphate minerals commonly found in samples from the Moon, Mars, and asteroids, but showing compositional diversity across different planetary bodies.

Magnesiochangesite-(Y) was discovered by a research team led by scientist Li Ziying from the Beijing Research Institute of Uranium Geology (BRIUG). The mineral appears as short columnar crystals, typically 2 to 30 micrometers in size, and is mainly found within basalt fragments in drilled lunar samples.

Researchers said the mineral's Chinese name plays on the homophone for magnesium  and "beauty", symbolizing a more beautiful and distinctive form of changesite-(Y). Ge Xiangkun, a researcher at the BRIUG, told the Global Times that magnesiochangesite-(Y) has a unique structure. Magnesium dominates the M site in its crystal lattice, and the particles are extremely small - about one-third to one-thirtieth the diameter of a human hair - making them invisible to the naked eye.

Identifying such a mineral was exceptionally challenging. Scientists analyzed tens of thousands of particles, comparing data repeatedly to isolate anomalies distinct from known minerals. Ultimately, they found only a single ideal crystal - just 20 micrometers wide - suitable for testing.

Handling the sample required extreme precision. Scientists had to transfer it between advanced instruments while carefully controlling airflow to avoid losing the particle. Extracting the crystal using a focused ion beam scanning electron microscope was likened to performing microsurgery, where even slight excess force could destroy the specimen, Ge said.

"As a new member of the merrillite group, magnesiochangesite-(Y) offers a fresh mineralogical sample for studying lunar formation, magmatic activity, and chemical differentiation, helping scientists better understand the Moon's geological history," he said.

Changesite-(Ce) was discovered by a team led by academician Hou Zengqian from the Chinese Academy of Geological Sciences. It was identified both in Chang'e-5 lunar samples and in a lunar meteorite that fell in China.

"Changesite-(Ce) is a phosphate mineral rich in the rare-earth element cerium, belonging to the merrillite group. Compared with minerals of the same group found in samples from Earth, Mars, and asteroids, it shows a clear enrichment in rare earth elements and thus serves as a 'fingerprint' planetary mineral," Hou told the Global Times.

He added that the newly discovered changesite-(Ce) shares the same structural model as the changesite-(Y) previously identified by Chinese researchers, but differs in rare-earth element occupancy: the former is dominated by the light rare-earth element cerium (Ce), while the latter is dominated by the heavy rare-earth element yttrium (Y).

Hou noted a key difference between samples returned by the Apollo program and those from Chang'e-5: Apollo samples tend to be enriched in heavy rare-earth elements, whereas Chang'e-5 samples show enrichment in light rare-earth elements. This suggests significant differentiation of rare-earth elements during the Moon's magmatic evolution.

The discovery is particularly notable because it is based on two distinct sample sources: lunar soil from the Oceanus Procellarum region collected by Chang'e-5, and a lunar meteorite named Pakepake 005 found in China's Taklimakan Desert in 2024 - the first officially recognized lunar meteorite discovered in the country.

The discovery of changesite-(Ce) was also highly challenging. Wang Yanjuan, the mineral's first discoverer and a researcher at the Chinese Academy of Geological Sciences, told the Global Times that during their study of samples from the Chang'e-5 mission and the first lunar meteorite recovered in China, the research team employed a range of advanced in-situ analytical techniques - including nanoindentation, cathodoluminescence, scanning electron microscopy, electron probe analysis, Raman spectroscopy, single-crystal X-ray diffraction, and three-dimensional electron diffraction - to systematically determine the mineral's physical properties, chemical composition, and crystal structure, ultimately confirming it as a previously unrecorded natural mineral.

The discovery of changesite-(Ce) not only broadens our understanding of the natural world, but also offers new possibilities for synthetic materials, Qu Kai, a member of the New Mineral Nomenclature and Classification Professional Committee of the Chinese Society of Petrology and Geochemistry, told the Global Times. He noted that the mineral exhibits a pronounced luminescent effect, showing strong potential for applications in the development of phosphor materials for white light-emitting diodes (WLEDs).

Academician Hou further explained that the discovery of the changesite-(Y) series minerals not only enriches the diversity of natural minerals - particularly those on the Moon - but also reveals the crystal chemical complexity of merrillite-group minerals in lunar soil, highlighting the diversity of the Moon's material composition and its evolutionary processes. As rare-earth-rich minerals, they also provide fundamental data for assessing the Moon's rare-earth resource potential and future in-situ resource utilization.