Fayalite is a mineral belonging to the olivine group, primarily composed of iron and silicate. Its chemical formula is Fe2SiO4, indicating that it contains iron (Fe) and silicon (Si) in its structure. Fayalite typically appears in shades of brown to black and is often found in igneous rocks, particularly in basalt and other volcanic formations. This mineral is significant in geology and petrology, as it helps scientists understand the conditions under which certain rocks form. Fayalite can also be associated with other minerals, such as forsterite, which is the magnesium-rich counterpart in the olivine group.