The density-driven structural transformations in ferrosilite glass FeSiO3 will be investigated at pressures increasing to 17.5 GPa. This glass is one of a family of silicate materials that have geophysical relevance because they form a significant component of the Earth's mantle. Indeed, the structural transformations that take place under the high-pressure conditions deep within the interior of the Earth govern key magma-related processes, ranging from present-day volcanic activity to the very early stages of Earth¿s formation. As for SiO2 glass, identifiable changes in the structure of FeSiO3 glass are expected to be observed as the density is increased. The new experimental information will be used for testing models for magmatic materials as obtained from molecular dynamics simulations using a polarisable ion model.