The Fall of the Gypsum Empire

Abstract The Roman exploitation of lapis specularis (selenite gypsum) in the Segóbriga district (Cuenca, central Spain) represents one of the most remarkable and yet understudied extractive industries of antiquity. Recent archaeological and geological research has revealed extensive underground networks exceeding 30 km in length, together with sophisticated engineering solutions for access, ventilation, and drainage. These findings demonstrate that lapis specularis mining reached a scale and complexity comparable to the major metalliferous districts of Roman Hispania. Beyond its economic significance supplying translucent windowpanes for elite architecture throughout the Empire this activity profoundly shaped the social and urban development of Segóbriga, transforming it into a prosperous mining municipium. The deposits themselves are exceptional, formed through Miocene paleokarst processes that favored the growth of large, transparent selenite crystals. Today, this unique combination of geology, archaeology, and cultural history endows the Segóbriga mining landscape with outstanding geoheritage value. Recognizing its patrimonial significance not only enhances our understanding of Roman resource exploitation but also highlights the urgent need for conservation, sustainable management, and public dissemination of these sites as part of Spain’s natural stone heritage.