The mineral coquimbite is a hydrated iron sulphate with the chemical formula Fe2(SO4)3 · 9 H2O. It has a trigonal-hexagonal crystal lattice and is bluish, purple, greenish or yellowish white in colour and transparent. The hardness is 2.0 to 2.1. Coquimbite is named after the Chilean region of Coquimbo, where the type locality is also located.