The age of iron meteorites implies that accretion of protoplanets began during the first millions of years of the solar system. Due to the heat generated by 26Al decay, many early protoplanets were fully differentiated with an igneous crust produced during the cooling of a magma ocean and the segregation at depth of a metallic core. The formation and nature of the primordial crust generated during the early stages of melting is poorly understood, due in part to the scarcity of availa…