We discovered a new rock type containing garnet inside a meteorite fragment from Mars

Garnet is a group of minerals that commonly occur on Earth. Pictured here, andradite garnet crystals from Madagascar. (Robert M. Lavinsky), CC BY-SA We discovered a new rock type containing garnet inside a meteorite fragment from Mars Published: June 23, 2026 3.52pm EDT Share article Print article On Earth, garnet is best known as the fiery red January birthstone — popular in jewellery since the Bronze Age and valued highly by ancient Egyptians. Our team has now discovered a new rock type containing the mineral garnet inside a meteorite fragment from the planet Mars. Victorian almandine garnet brooch. (Charles J. Sharp), CC BY-SA While garnet is common on Earth, we have previously only speculated about its existence in Mars’s interior and found rare, minute inclusions in Martian meteorites that formed during their ejection from the planet. This is the first time the mineral has been identified within a rock that potentially formed within the crust of Mars itself. As a planetary scientist and geologist, my main goal is to study the chemical and mineral makeup of rocks on Mars to help piece together the planet’s complex history. Our discovery of a new garnet-rich rock type is a significant step towards that goal. Minerals preserve history Mars has been the target of numerous exploration missions since the 1960s by satellites, landers and rovers. Read more: Did NASA’s Curiosity rover find signs of ancient life on Mars? An astrobiologist explains how we determine ‘life’ While the search for signs of past life has driven these efforts, it is the inorganic components of Mars — its rocks and minerals — that preserve the record of the planet’s 4.5 billion-year history. Minerals and rocks are produced by complex interactions among the geosphere, atmosphere, hydrosphere and even the influence of life. Detailed analyses of newly discovered rocks and minerals can help us understand how a planet’s geological processes, climate and resulting habitability potential have evolved over time. An andradite garnet Demantoid garnet from Madagascar. (Rob Lavinsky), CC BY-SA Garnets are a group of minerals with the same crystal structure and a range of chemical compositions. Some of the most common species within this group include almandine and pyrope (the deep-red January birthstone gems), andradite and grossular. The rock we have identified contains garnet of the andradite variety. It can come in many colours, but is often yellow or green. It, too, has been…