The Berbes mining area, in Ribadesella Asturias, Spain is a classic for Spanish minerals from its mines many world-class specimens have been extracted. Undoubtedly, the most emblematic exploitation of all was the Ana mine (his first complaint dates from 1910, for Fe), which was developed through inland mining, but with a not very long period of activity (1949-1968) impossible to access At present, but there is work in seams in outdoor mines such as La Cabaña or Los Cobayos where it is still possible to chop and with luck take some samples, that is if you will have to break some chisels in that hard matrix.
A singularity that this red fluorescence has under LW is that after a long time of exposure it fades and can recharge by exposing it to SW for a while.
Apparently more and more localities are added for this type of fluo but I think that Berbes continues to be the largest at the least of those I have seen.
This is not one of the largest only 7 cm edge and 15 x 13 cm total piece.