they contain 19–22% total iron and only 0.3–3% metallic iron. that means that most of the iron is present as iron oxide (feo) in the silicates; olivine contains 26 to 32 mol% fayalite (fa). the most abundant minerals are hypersthene (a pyroxene) and olivine. other minerals include fe–ni, troilite (fes), feldspar or feldspathic glass, chromite, and phosphates.