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Boñar stone is an Upper Cretaceous (Coniacian-Campanian) limestone that crops out near the village of Boñar, in the province of León, northern Spain. Geologically, it has been traditionally called the Boñar Formation, an eminently carbonate succession with sandy and clayey intercalations, which in some sectors is over 300 m thick. The calcarenitic and alternating members are exploited to obtain masonry stone, corresponding to sparitic limestone. The dolomitic member was used in the construction of the historical architectural heritage and it is still used now for new constructions. In the region, there are numerous small indications in which Boñar stone was historically exploited, but currently only the Sierra Redonda quarry remains active. Its use in architectural historical heritage is extensive in the province and in the city of León, with outstanding examples such as the Cathedral of Santa María de la Regla, the Hospital of San Marcos and the Royal Collegiate Church of San Isidoro, among many others. Its use has been confirmed since the 10th century in the construction of the arcade of the basilica of the nearby monastery of San Miguel de Escalada, and it is also employed over the Romanesque (San Isidoro) and the Gothic (Cathedral) periods. In short, this material has made it possible the construction of all these master Hispanic architectural examples over its different historical stages. It is currently used as a construction material with different purposes in different parts of the Spanish geography and it is also exported abroad to be used, for example, in the construction of the New Town Hall building in Malabo (Equatorial Guinea) and in some constructions on the Caribbean Island of Aruba