The Pyrenean Axial Zone is characterized by thick series of metasedimentary and orthogneissic materials derived from pre-Variscan rocks. These sequences were intruded by large bodies of Variscan granitoids, some exposed after the Alpine orogeny. In the Eastern Pyrenees, a number of quartz veins of kilometric length and metric to decametric width, are present. Although these veins are mostly hosted by Variscan and pre-Variscan rocks, in the utheastern limit of the Roc de Frausa Massif, large fault related quartz bodies rossc utting Mesozoic sedimentary rocks, have also been recognized Liesa, 1988). The Roses giant quartz vein constitutes a remarkable example of the seregional scale quartz veins. It is located at the south ernportion of the Cap de Creus Massif, extending for 2700 mand reaching widths up to 25m. Apparently, the vein continues towards the NW depicting a much longer structure.