(1963) demonstrated that granite powder was dissolved in
cultures of fungi isolated from the surface of granite rocks
in Scotland. Most of the above-mentioned acids can also react
with cations present in rock-forming minerals by chelating
them. The cations in the minerals are exchanged, which
results in a change in the physical and chemical properties
of the rock (Krumbein et al., 1987). The decomposition of
silicates results in the formation of free silica, the resulting
acidity stimulating the dissolution of minerals and the
growth of fungi.