The Wallace Collection, London has one of the most important collections of Indian Arms & Armour outside the subcontinent. Museum objects must be studied non-destructively, which makes their analysis difficult. However, we have collected some (broken) blades from the Arsenal of Hyderabad and examined them by metallography. Neutron diffraction carried out on these specimens will enable us to relate the ND lattice parameters to the proportions of the known phases present. Thus we hope to develop a non-invasive method for characterising the crucible (high-carbon) steels which differ greatly from modern materials, but which were used in making these swords, shields and helmets. As well as a means of identifying their places of origin, such knowledge can inform decisions on their conservation.