Além Paraíba Mylonite as a Heritage Stone of the Paraiba Do Sul Valley, Rio De Janeiro, Brazil

Abstract Além Paraíba Mylonite (APM), occurring within the NE–SW-trending Além Paraíba Shear Zone in southeastern Brazil, represents a unique geodiversity element and cultural heritage of the Paraíba do Sul Valley, spanning municipalities in the states of Rio de Janeiro and Minas Gerais. This ductilely deformed rock, associated with Neoproterozoic tectonic processes of the Brasiliano–Pan-African orogeny, has been widely used in historic constructions in the region during the nineteenth and twentieth centuries. This study documents the geological, technological, and heritage aspects of Além Paraíba Mylonite (APM) through field surveys, bibliographic research, and laboratory analyses. Quarry sites across the region were mapped, highlighting their scientific, educational, and geoheritage relevance. Blocks from orthogneissic and paragneissic mylonite were characterised for density, porosity, water absorption, mechanical strength, hardness, and colour, revealing properties suitable for civil construction and ornamental uses. APM was extensively employed in religious, civic, and elite residential architecture, as well as in infrastructure, engineering works, paving, and commemorative monuments, demonstrating its versatility and durability. Its presence in urban furniture, bridges, railway stations, fountains, and cemeteries further illustrates its cultural and symbolic significance. The integration of geological and historical data emphasises APM as both a building material and an element of regional identity. This comprehensive documentation supports the conservation, dissemination, and appreciation of Além Paraíba Mylonite as a tool for understanding the Earth’s processes that shape the natural environment and the cultural heritage in the Paraíba do Sul Valley in the state of Rio de Janeiro, reinforcing the link between geology and cultural identity. The study contributes to strategies for safeguarding historical constructions while promoting awareness of the region’s geological richness.