Analysis of an ancient meteorite from Mars suggests that the mineral zircon may be abundant on the surface of the red planet. By determining the age and hafnium isotope composition of these zircons, researchers have shown that a population of these crystals were sourced from the deep interior of Mars. If the researchers are correct, it means that the young zircons contain information about the deep, inaccessible interior of Mars, which provides insights into the internal structure of the planet.