The Alteration of Giglio Island Granite: Relevance to the Conservation of Monumental Architecture

The research examines the alteration phenomena of Giglio island granite, a rock quarried by Romans from 3rd century, used for columns in Italian peninsula and later reemployed many Christian religious buildings. study has shown that already bedrock there are small percentages clay minerals. Starting this condition, develops an increase porosity, which turn favours establishment slight hydrolysis silicates with decrease Na, Ca, K, accordance sericitisation process. proceeds further apparently not related to real loss cohesion, which, however, occurs shortly after, highlighting necessity continuous monitoring state conservation material architectural heritage.