The list currently names 32 varieties that have played a role in architecture and culture beyond the borders of their homeland

Arrábida Breccia (Brecha da Arrábida) has been included in the Geoheritage Stones list. It is a natural stone from Portugal that has played a major role in architecture and culture there and in many other countries over many centuries. It is known – among other things because of its red color – under names such as Jasper Stone, Ancient Red, Red Sandstone, Arrábida Conglomerate, Arrábida Mosaic Marble, or Portugal’s Breccia.

Thirty-two stones currently make up the list. Two ornamental stones from Portugal have been included in the list so far, namely the Estremoz Marble and the Lioz Limestone.

A committee of the International Union of Geological Sciences (IUGS) decides on the inclusion in the list. Applicants must provide a detailed and scientific summary of the petrographic characteristics of their stone and its cultural significance. The Geoheritage Stones definition states, “a natural stone that has been used in significant architecture and monuments, recognized as an integral part of human culture.“

Brecha da Arrábida has been quarried and used as a building stone in Portugal since Roman times. From the 15th century, associated with the splendid architectural style of Manueline, the stone was used more for artistic works on public buildings, according to the documents. Buildings and works of art from that period can be found in Portugal and another 6 countries on 3 continents, mainly Austria, France, Spain, the United Kingdom, Brazil, and Mozambique.

Famous buildings in Portugal are for example the Convento de Jesus (Monastery of Jesus) in Setúbal and numerous buildings in Belém.

From the 17th century on, it is found only as a decorative stone in the interiors of buildings.

In the 1970s, mining was stopped because all quarries are located in the newly created Arrábida Natural Park. Currently, there are efforts to reopen parts of the quarries for the restoration of historic buildings.

The application documents state: “Geologically, the Brecha da Arrábid consists of an Upper Jurassic (about 160 million years old) intraformational conglomerate breccia, of granular support, with carbonate clasts of different colors, in a carbonate-red clay cement, whose genesis is associated with karst formed during a generalized emersion event in the Lusitanian Basin when the West Iberian Margin and Newfoundland Margin were stretching apart.“

Portuguese geologists want to use the new status of their natural stone for public relations. The documents state: “The next urgent actions to be implemented, mainly in the Jasper quarry involving the municipalities and the Natural Park are the improvement of conditions for visitation, and the paths to access them, the placement of information plates and the establishment of organized tours for pedagogical purposes and public awareness for the need of preservation. The recent classification as HS was of utmost importance and contribution to achieving these goals.“

The application to IUGS was made under the leadership of José Carlos Kullberg, professor at the Universidade Nova de Lisboa and Dr. António Prego, currently a high school teacher in Almada, and the professors at the University of Évora Luís Lopes, Tiago Alves, and Ruben Martins.

Source: Kullberg, J., Prego, A., Lopes, L., and Alves, T.: The “Brecha da Arrábida”: new historical findings, geographic dissemination, and geotechnical contributions for the classification as Heritage Stone, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8401
https://meetingorganizer.copernicus.org/EGU23/EGU23-8401.html

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(07.06.2023, USA: 06.07.2023)