Pyrite decay - into the great unknown

Abstract

More than 200 years of research have brought us little closer to understanding, let alone controlling, pyrite oxidation in geological collections. This appears paradoxical, because thousands of papers have been written on the deterioration of iron sulfides by geochemists, engineers and conservators. But whilst reaction products and pathways are characterised well, the causes of deterioration of different types of iron sulfide specimens in geological collections remain elusive. To make matters even more complicated for the museum conservator, published guidelines for the management of such specimens are patchy and often contradictory. Currently available condition assessment methodologies are barely suitable for routine monitoring of large collections, results of specimen monitoring exercises are not necessarily replicable, and, in the absence of guidance on suitable storage conditions, triggers for, and suitability of, conservation actions are difficult to determine. A new approach is required to end the guess work and add some substance, based on evidence, to the collection care of geological collections in museums. This paper does not answer these questions but introduces a framework for a research agenda that would underpin a robust approach to the delivery of preventive conservation of geological collections. This includes a definition of what kind of material change in minerals constitutes damage; categorisation of damage/change; development of a protocol for routine condition assessments; the definition of an adequate storage environment; and testing rigorously the suitability of conservation treatments.