Hexaferrum
Hexaferrum, also known as epsilon iron, is a form of iron at very high pressure. Hexaferrum is often compared to cobalt. Hexaferrum is a (formula: Fe, Os, Ru, Ir) hexagonal-dihexagonal dipyramidal yellowish steel-gray mineral containing iridium, iron, osmium, and ruthenium. It was named for the crystal morphology, being in the Hexagonal system, and its composition, containing essential iron.