Ançã Limestone, an IUGS Heritage Stone in the UNESCO World Heritage Site “University of Coimbra – Alta and Sofia” of Portugal

Abstract Ançã Limestone is a light-coloured, fine-grained Jurassic limestone traditionally extracted in the municipality of Cantanhede (Central Portugal). Owing to its softness, homogeneity, and capacity to retain fine sculptural details, it has become one of the most widely used ornamental and building stones in Coimbra from the Middle Ages to the present day. Its use is especially prominent in the architectural and sculptural ensemble of the “University of Coimbra – Alta and Sofia”, inscribed on the UNESCO World Heritage List in 2013. This study documents the geological characteristics of Ançã Limestone, its historical extraction, and its role in shaping the architectural identity and artistic production of Coimbra across the Gothic, Manueline, Renaissance, and Baroque periods. The stone’s physical properties influenced major sculptural traditions and contributed to the creation of emblematic monuments carved by renowned masters such as Mestre Pêro, Diogo Pires (The Elder and The Young), Jean de Rouen, and Claude Laprade. This article also examines the stone’s vulnerability to decay, summarising the current knowledge on its weathering behaviour, decay patterns, and conservation challenges. The recent designation of the Ançã Limestone as an IUGS Heritage Stone underscores its international relevance, promoting the documentation, conservation, and sustainable management of this culturally significant material. By integrating geological, historical, and conservation perspectives, this contribution highlights the importance of the Ançã Limestone as a key component of Portugal’s geoheritage and as a material cornerstone of the Outstanding Universal Value of the “University of Coimbra – Alta and Sofia”.