THE CANDOGLIA MARBLE FROM VERBANO CUSIO OSSOLA QUARRY BASIN (NORTHWESTERN ITALIAN ALPS): CHARACTERIZATION, QUARRYING EVOLUTION AND APPLICATION FOR THE MILANO CATHEDRAL CONSTRUCTION

The Candoglia Marble is one of the best known stone resources among the Alpine Italian marbles. It has been and is still exploited in the Verbano-Cusio-Ossola (VCO) area with lenses cropping out close to the villages of Candoglia and Ornavasso. These lenses are interlayered within high-grade paragneisses of the Ivrea Zone, a section of deep continental crust that experienced amphibolite-to granulite-facies metamorphism during the Palaeozoic. The marble is a pinkish, coarse-grained, calcitic marble with frequent, cm-thick, dark-greenish silicate layers containing diopside and tremolite.

The first record of marble quarrying activities in the area occurred during Roman period; marbles were widely employed in local construction but they became famous thanks to their use for the “Duomo di Milano” (XIV century). Initially the building stones employed for the construction of the Duomo di Milano were quarried in the Ornavasso area. However after a short time, the Candoglia quarry became the main quarry for the construction and maintenance of the Cathedral. (several small open pit quarries at the beginning up to a unique underground quarry, at present).

The Candoglia Marble was preferred to Carrara marbles because of the more direct transport routes: marble blocks and semi-finished products were carried on large barges, from the Toce River (VCO), across the Maggiore Lake and the Ticino River, and then along the Naviglio Grande, up to the Milano Cathedral yard.

Candoglia Marble is an example of how a stone resource can be intended as "cultural heritage". Indeed, the heritage connected to stone exploitation marks out the VCO: a territory in which stone workers live, characterizing and influencing the local culture. The human activities connected to the Candoglia Marble (exploitation, processing, transport, construction and maintenance of the Duomo di Milano) has occurred across seven centuries and the quarry itselftestifies to the history and evolution of the VCO area.

The Candoglia quarry provides a source of a “natural good”, the Candoglia marble, which interacts with an “anthropic good”, the Milano Cathedral. The close connection between Stone and Man and the world-wide importance of the Duomo di Milano, lead us to consider the Candoglia Marble as a significant example of what is meant by Global Heritage Stone Resource.