Answer:
Olivine, with the formula (Mg,Fe)₂SiO₄
Explanation:
Olivine is a mineral with the formula (Mg,Fe)₂SiO₄. It is a magnesium iron silicate (or ferromagnesian mineral) that constitutes the largest part of the earth's upper mantle. The mantle is the second layer of the earth found in between the core (below) and the crust (on top). It accounts for about 84% of the earth's volume (as regards the layers of the earth).
