ALMADEN or ALMADEN DEL AZOGUE, a town in Spain, province of Ciudad Real. Pop. (1920) 9,829. Almaden (Ar. amaden, the mine) has been for centuries the principal centre for the famous ores of mercury, impregnating the quartzite of certain ridges between the Sierras of Chillon (N.) and Cordoneros (Alcudia) (S.) . The Sisapo of the Romans lay in the same neigh bourhood. Almaden and Adria (Southern Austria) were the chief sources of mercury till New Almaden (California) was\opened up They were long worked by convicts owing to the unhealthy atmosphere and exemption from military service is granted to miners who have worked at Almaden for two years.
See Minas de Almaden (Madrid, 1926), guide-book, XIVth. Int. Congr. of Geol., with diagram showing entire production of the mines since the 15th century.