Conservation of natural stone

Natural stone has been used in many historical structures all over the world. Pieces of stone taken directly from nature - whether or not worked - were used for a wide range of objects many centuries ago already. Old stone constructions such as Stonehenge near Salisbury in England, the Parthenon on the Acropolis in Athens, the Borobodur on Java, but also the many medieval cathedrals in France appeal to everyone’s imagination. It was mostly such traditional monuments that brought John Ruskin and Eugène Viollet-le-Duc to their opposing views on conservation and restoration. The principle of minimum intervention, described in the Burra Charter (1999) as doing as much as necessary and as little as possible echoes through many national and international charters and other policy documents. It is widely supported, but in the case of natural stone conservation, this principle does not provide an unambiguous direction. [...]