Mossbauer spectroscopy, SEM and microprobe analyses were used to study a na
turally occurring and a synthetically produced mineral. Valleriite is a com
plex layered mineral and varies on the basis of crystal structure, composit
ion and occurrence. The Mossbauer technique was used to characterize and de
scribe it. The valleriite studied contains iron in the 2+ and 3+ oxidation
states and the proportions of the two states were calculated. Pyrite was sy
nthesized by reacting Fe2+ and S2O32- and the compound thus produced can be
used in the manufacture of thermal batteries. The Mossbauer, SEM and X-ray
data of the synthesized pyrite were compared with information on naturally
occurring pyrite and other iron sulphides.