When Earth's iron-metal core separated from its silicate mantle, elements more soluble in metal than in silicate were transferred to the core. After core formation was complete, these elements were added back to the mantle by accretion of meteoritic material. Dauphas1 considers the elements titanium, chromium, nickel, molybdenum and ruthenium (listed in order of their increasing preference for the core). Using the isotopic differences in these elements between Earth and meteorites, the author shows that our planet formed from a mixture of meteorite types during the first 60% of its growth and subsequently almost entirely from oxygen-poor meteorites called enstatite chondrites. Fischer-Gödde and Kleine2 use high-precision ruthenium isotopic measurements to confirm that the last 0.5% of the accreted material was most like enstatite chondrites.