THE 1ST OCCURRENCE OF SCHWERTMANNITE IN A NATURAL STREAM ENVIRONMENT

After being frequently identified in precipitates from acid mine water s, a fully natural occurrence of schwertmannite, Fe16O16(OH)12(SO4)2, has now been found in a small stream draining a pyritic schist at the Pfitscher Joch, Zillertaler Alps, Austria. The characteristics of spec imens from this location are in full agreement with those of synthetic samples and samples from acid mine waters described elsewhere. This n atural occurrence also demonstrates the genetic relationship between s chwertmannite, jarosite and goethite/ferrihydrite as products of pyrit e oxidation, which is governed mainly by the pH and the sulfate and ir on concentrations of the stream.