Forsterite-rich olivine is the most abundant mineral in the mantle above a depth of about ; pyroxenes are also important minerals in this upper part of the mantle. Although pure forsterite does not occur in igneous rocks, dunite often contains olivine with forsterite contents at least as Mg-rich as Fo92 (92% forsterite – 8% fayalite); common peridotite contains olivine typically at least as Mg-rich as Fo88. Due to its high melting point, olivine crystals are the first minerals to precipitate from a magmatic melt in a cumulate process, often with orthopyroxenes. Forsterite-rich olivine is a common crystallization product of mantle-derived magma. Olivine in mafic and ultramafic rocks typically is rich in the forsterite end-member.