The Nossa Senhora Assunção Pegmatite in Northern Portugal is a typical quartz - feldspar pegmatite, which is mined primarily for feldspar. The pegmatite is famous for a variety of beryllium minerals like bertrandite, phenakite, beryl and of rare phosphate minerals like xanthoxenite, siderophyllite, zwieselite and montgomeryite. For a more detailed listing of minerals and some more photos please have a look at mindat.org

The Assunção pegmatite is also famous for its giant beryl crystals, which occcur in often perfectly hexagonal crystal shapes in the quarz - feldspar matrix. They display a light green to sometimes intense green colour and may reach several meter in length. As can be seen in the photo above, the beryls are often surrounded by a black micaceous surrrounding. Apart from the beryl crystals large quartz crystal cavities are known to occur sporadically.

In 1994 a single beryl crystal of 1,20 m length was recovered from the quarry and after some years in a private mineral collection it was recently donated to the Geological Collection of the Bergakademie Freiberg, Saxony, Germany, where it is on display now.