One way in which nanoparticles may differ from bulk properties are in terms of their response to pressure, but at the present time there have been very few structural studies of nanoparticles under pressure. There is the possibility that nanoparticles will show different elastic properties under pressure. We are able to produce nanoscale magnetite, Fe3O4, reproducibly. We propose to study a range of nanoparticle sizes down to 5 nm of magnetite, and compare with bulk magnetite, up to pressures of around 10 GPa. Rietveld refinement will be used to characterise the volume and structure, with a focus on understanding the way that local coordination polyhedra change under pressure.