What is a mafic mineral?

1 Answer
Jan 1, 2016

A mineral that is high in elements such as magnesium and iron.


Mafic minerals contain a high proportion of the elements magnesium and iron. Magnesium provides the prefix 'ma-' in 'mafic'. The rest of the name comes from 'ferric', meaning 'iron'.

These minerals are common in the Earth's mantle and in silica-poor rocks. They include olivine, pyroxene and biotite mica, which are all known for having distinctive dark colours.

They also tend to be less stable on the Earth's surface than other minerals. Sometimes olivine from the mantle is brought to the surface in a volcanic eruption, where it weathers into an orangey clay mineral.