With regard to the occurrence of the mineralizations in W and Sn in Portugal, the "Província metalogenética estano-tungstífera Ibérica" (Iberian tin-tungsten-metallographic province) extends to the east of the shear Porto-Coimbra-Tomar and to the northeast of the Juromenha thrust. With the exception of the deposits linked to the granite of St.ª Eulália (ZOM - Zona de Ossa Morena – Ossa Morena Zone), the remainder are located in the Zona Centro-Iberica (Central-Iberian Zone) (ZCI), Zona Galiza Média-Trás-os-Montes (ZGMTM) and Zona Asútrico-Ocidental-Leonesa (Astúrico-occidental-leonesa zone) (ZAOL). The Portuguese tin-tungsten metallographic province develops throughout the central and northern region of Portugal where the vein deposits are undoubtedly of greater economic importance.