Picrite is a type of igneous rock rich in magnesium. It is chemically defined according to the IUGS as those with contents of: * SiO2 between 52 and 30 wt% * Na2O + K2O less than 3 wt% * MgO greater than 12 wt% wt%, which correspond to komatiite and . The picritic basalt or picrobasalt is a variety of basalt abundant in olivine and with a matrix of augite, labradorite, opaque minerals and glass. Oceanite is a variety of picritic basalt.