Although many fungi are known to be able to perform bioweathering of rocks and minerals, little information is available concerning the role of basidiomycetes in this process. The wood-rotting basidiomycete Schizophyllum commune was investigated for its ability to degrade black slate, a rock rich in organic carbon. Mechanical pressure of hyphae and extracellular polymeric substances, for which schizophyllan was identified, investigated for biophysical weathering. In addition the secretion of siderophores and organic acids as biochemical weathering agents was shown. While previously, the exoenzyme laccase was believed to attack organic matter within the black slate, thereby releasing metals from the rock, enhanced dissolution of quartz phases by etching and pitting could be seen in this study. At the same time, the formation of a new secondary mineral phase, whewellite, could be demonstrated.