Keilite is an iron-magnesium sulfide mineral (chemical formula (Fe,Mg)S)) that is found in enstatite chondrites. Keilite is the iron-dominant analog of niningerite. Keilite is named after Klaus Keil (born 1934).
Examples of keilite occurrences are enstatite chondrites and the Zakłodzie meteorite. It appears to be confined to impact-melt influenced enstatite chondrites that were quenched. There are also some meteorites interpreted as impact-melt breccias that don't contain keilite. This is explained as a deeper burial after impact, which slowed cooling and enabled retrograde reactions (diapthoresis) to take place.