PHARMACOSIDERITE on Chalcedony

SPECIMEN DESCRIPTION

This is an interesting locality specimen from the Martin and Michael Günther collection. Pharmacosiderite is reported from Schneeberg, Erzgebirge, Saxony, Germany on Mindat.org but finding images is another matter. This miniature specimen is quite distinctive, consisting of siliceous host rock with a cavity lined with white finely botryoidal Chalcedony - a cryptocrystalline variety of Quartz. Sat upon the bright white Chalcedony are at least three dark orange cubic, or cuboid, Pharmacosiderite microcrystals - sub mm in size. An old typed number label (303) attached to the specimen suggests that it is an older specimen, but that aspect of its history is not known.