Giant beryl crystals in the Assunção (Ascensao) Pegmatite mine,
Northern Portugal, displaying intense green colour

Photo : R. Hochleitner, Munich

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Beryl - Beryll - Beryl - Berylo Europe : Portugal : Viseu District : Giant beryl crystals in the Nossa Senhora Assunção (Ascensao) Pegmatite 40°49'N , 7°37'W : Aldeia Nova, Ferreira de Aves, Satao, Viseu District, Portugal

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 both beryllium minerals like betrandite, phenakite, beryl and 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) and search for the keyword 'Assunção'. The Assunção pegmatite is well known 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 beryl are often surrounded by a black micaceous surrrounding. Apart from the beryl 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 Geowissenschaftliche Sammlung der Bergakademie Freiberg, Saxony, Germany, where it is now on display.   The Nossa Senhora Assunção pegmatite in a nutshell : Mineralogy : Beryl crystals in feldspar - quartz matrix. Crystal Size : Several meter long beryl crystal are known to occur sporadically. Geology & Formation : Pegmatitic Current status : Active feldspar / quarz quarrying operation Remarks : The locality probably hosts the largest beryl crystals in Europe.   Other notable & famous beryl occurences : Note : Beryl and many of its varieties tend to form large crystals and crystals up to 1 m are by no means rare. - Beryl crystals up to 9 m long and weighing 61 tons were found in the Keystone area, South Dakotah, USa. - Several meter long beryl crystals are also known from the Bumpus Quarry in Maine, USA - The largest known gem aquamarine of 110 kg, was found in the Papamel mine, Maraimba, Minas Gerais, Brazil, in 1910: Other giant aquamarine crystals up to 3 m lenght were discovered recently in the Jatoba Mine, Santa Maria de Itabira, Minas Gerais, Brazil. - Beryl crystals up to 18 x 3 m (!) have been reported from various localities in Madagascar, such as Malakaina, Ankazobe and Tasantanana. - Aquamarine crystals up to 1,5 m length are known from Tigerek, Rudnyy Altay Mountains, GUS. - Rarely beryl is found replacing fossil molluscs. A notable occurence is Muzo, Columbia, where - beside huge quantities of excellent gemmy emerald crystals - bright green fossil shells have been found, which are totally "emeraldizied".

Giant beryl crystal in the Assunção pegmatite, reaching about 4 m length Photo Source : Rui Nunes   The Asuncao pegmatite quarry, mined for industrial feldspar. Photo Source : Rui Nunes     Resources and relevant weblinks : For more information on the mineral beryl please look at www.mindat.org, Webmineral and the german Mineralienatlas. There seemed to be not very much published information on this locality, but the large beryl crystal mentioned in the text above is on display in the Geowissenschaftliche Sammlungen, Freiberg, Germany