Tin weathering experiment set by nature for 300 years: natural crystals of the anthropogenic mineral hydroromarchite from Creussen, Bavaria, Germany

Abstract

Hydroromarchite is a mineral that so far has been found only in a few locations in the world and recognized as a common product of submarine corrosion of pewter artefacts. Here we report a new locality for this rare mineral found at the Saint James Church archaeological site in Creussen, Germany. There it appeared to be a product of weathering of a tin artefact (a tin button) buried in soil of the churchyard for about 300 years. The mineral, found in paragenesis with romarchite and cassiterite, was identified using single-crystal X-ray diffraction.