Pyrite, galena, sphalerite, and marcasite. Freihung Mine, Oberpfalz, FGR
A fragment of fossil wood has been replaced by sulphides. Pyrite (light yellow, bottom) and minor marcasite (light green-yellow, higher reflectance than pyrite, bottom right) have replaced the cell walls and cells of the wood. Within the cells, marcasite is surrounded by pyrite (centre bottom). Surrounding the iron sulphides, the wood has been replaced by galena (light blue-white) and sphalerite (light grey, top left), with sphalerite enclosed within galena. Dark grey areas are gangue.
Polished block, plane polarized light, x 80, air