Pyrite oxidation; protection using synthetic resins

Pyrite specimens may undergo severe damage due to oxidation and humidity in museum environments; the use of fluorinated, acrylic and silicone resins as protective films has been investigated using Elba pyrite in a climatic chamber and in acid oxidizing solutions. Acrylic resins show scant protection in the presence of UV rays and a general tendency to yellowing. In a humid environment and in fully aqueous conditions, silicone resins do not isolate the specimen, allowing water to reach and oxidize the sample surface. Fluorinated resins are relatively better at providing shielding films, allowing a high degree of protection and giving complete transparency; the resins tested, however, do not provide an absolute insulation of the samples, making ion-exchange possible.