at 33 quintals per cubic metre and, when smooth, it has a textured matte sheen. The characteristic that makes it immediately recognisable is its consistently purplish-red colour. The versatility of this sandstone withstood competition from marble in the Middle Ages. Marcello Ricardi wrote in Article 1 of the magazine 'L'Ogliolo', 'Owning the portal of the Simona stone house means that a family can be seen in Vicinie, either for personal wealth or political influence. In many villages in the Camonica Valley these structures are still intact, and the date of the inauguration is often engraved...'. Hydrography Beneath the historic centre of Erbanno there is a river floodplain, today houses and industry are everywhere, but until a few decades ago it was a cultivated area. Thousands of years ago this plain was the site of a lake basin, which extended from today's Lake Iseo to Cividate Camuno. This is due not only to the nature of the subsoil, but also to the presence of evident fishing tools, such as simple nets and cages, in the rock carvings of the area. The territory of the municipality of Darfo Boario Terme includes, in addition to the river Oglio, the streams Dezzo, Rovinazza, Budrio, Re, Ogliolo and the Italsider hydroelectric power stations. Since ancient times, rivers and streams have been seriously damaged by floods. We need only recall the extremely serious disaster caused by the collapse of the Gleno dam (1 December 1923) and the flood of 16 September 1960. Origins of the name According to Olivieri, the name is a compound word 'ad arvum', meaning 'present'. According to Mario Gallotti, it derives from the Mediterranean word arbe', which is the name of the Alpine river. Some scholars believe it originated from the German "Dorf" (village). Don Lino Ertani has suggested that Darfo derives from the ancient dialect word "Garf" (landslide, gravel and rock). The dialect pronunciation is actually "Darf" and would indicate the rising of the terrain of ancient Darfo and the descent of the cones of the Rovinazza and Re streams, which brought numerous boulders and debris downstream. Sights Terme di Boario History Antonio Bazzini, as he wrote in "Cronaca di Lovere", claimed that the history of Boario Terme as an excellent health resort began when the Casino di Boario was built, where "salutary magnesic and iron vitrinolate waters" were managed. According to some scholars, however, knowledge of the waters of Boario