Ochre granite stones in the tomb of the king Oserkon II at Tanis, Lower Egypt, were subjected to continuous kaolinization by microbiota composed of Pseudomonas aeruginosa, Streptomyces spp., and Yarrowia lipolytica (Candida). These microorganisms involved significantly in kaolinization of granite stones into clay minerals that their rosy color turned into grey color due to the acidolytic activity of attached microorganisms and clay mineralization. Grey film on the kaolinized granite stones contained a higher calcium ions and lower ferric ions. On the other hand, quartz appeared in form of separated crystals that caused roughing of granite surfaces in the investigated tomb.