Source: wikibot/greigite
= Greigite
{wiki=Greigite}
Greigite is a mineral with the chemical formula Fe3S4, which indicates that it is a type of iron sulfide. It is a rare mineral and is often associated with other iron sulfides such as pyrite (FeS2) and marcasite. Greigite has a distinctive black or dark gray color and typically occurs in sedimentary environments, often found in association with organic matter.