Island with a mica quarry in complex pegmatites similar to the ones on the nearby Utö.
Ref:
Gustafsson, Lars & Otter, Bertil (1991): Mineralförekomster i Stockholmstrakten.Del 2. STEIN 18(4),4-12
Beryllium phosphates from the Proterozoic granitic pegmatite at Norrö, southern Stockholm archipelago, Sweden
GFF (1993) 115 (2), 159-164.
Canadian Mineralogist (1998) 36 (2), 377-394