| Abstract: | AbstractThe recent development of a phosphate hardening paste without oxalates, as well as consideration of the mixed calcium oxalate-phosphate composition of the hardest urinary stones, provide evidence to suggest that the formation of some patinas is the result of old protective treatments on stone surfaces. The formation of patinas with phosphates and oxalate scialbatura on marble and limestone is discussed as a contribution to the debate amongst conservators and scientists about the nature, composition and origin of these patinas. It is concluded that for the formation of both the inner part and the outer part of the patinas, the concurrent action of microorganisms and man is necessary. In both cases, man provides the foods and the microorganisms effect the transformation. |
