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Improving Mindat.orgPoncione d'Alnasca, Verzasca Valley,Ticino, Switzerland

15th Dec 2014 15:14 UTCHartmut Hensel Expert

The locality Poncione d'Alnasca lists quartz and smoky quartz with reference to Jordi Fabre specimens. But the associated photo descriptions state "Val Maggia, Canton Tessin, Switzerland". Val Maggia (Maggia valley) is a completely different valley than Verzasca valley and the "Poncione d'Alnasca" mountain is not on the border of both valleys.

So what is correct now? The photo descriptions? Then the mineral list for the locality might be wrong. Or the mineral list, but then the photo descriptions are wrong. I personally assume that the photographed quartz crystals are correctly labeled, but are coming from a completely different locality in Maggia valley.

Could someone kindly clarify?

Cheers

Hartmut

15th Dec 2014 18:53 UTCUwe Kolitsch Manager

Message sent.

8th Jan 2015 20:22 UTCHartmut Hensel Expert

One photo has been removed in the meantime, but the other one is still assigned to the locality. And still the mineral list is not changed or the references updated.

I also doubt that the listed Zoisite var. Thulite is correct. There is no reference given and it might be a wrong interpretation of the description given in "Mineralienlexikon der Schweiz" p. 152 where it is stated that Thulite is known from the "northern side of P. d'Alzasca in Maggia Valley". But Pizzo d'Alzasca in Maggia Valley is not the same as Poncione d'Alnasca in Verzasca Valley.

Can anybody from the swiss colleagues comment on all that?

Cheers

Hartmut

28th Mar 2016 18:58 UTCUwe Kolitsch Manager

Quartz and smoky quartz removed from list.

According to uploader of "thulite" photo, the specimen was obtained from a Swiss collector.

Have changed the thulite" to clinozoisite-epidote series and added caption.

http://www.mindat.org/photo-734329.html

28th Mar 2016 23:19 UTCPaolo Bosio

Photo http://www.mindat.org/photo-734329.html unequivocally shows zoned crystals of epidote group (i.e. crystals consisting of green epidote, colourless clinozoisite, and violet-lilac piemontite) from Maurino quarry (Cava Maurino), northern slope of Pizzo Alzasca, Linescio, Campo Valley (Valle di Campo), Maggia Valley. The epidote-group zoned crystals from this locality may sometimes contain an orange-coloured zone of Mn-bearing zoisite. The correct description of these crystals is given in Stalder et al. (1998): Mineralienlexikon der Schweiz, page 152.

However, in the first reports on these crystals (see Weiß S. (1982): Piemontit vom Poncione Alzasca, Tessin. Lapis, 7, 7, 55-58+73; Weiß S. (1986): Alpine Kluftvorkommen von Thulit und Piemontit im Tessin. Lapis, 11, 3, 34-35) the locality was generically indicated as Poncione Alzasca with no mention of the quarry. I personally know mineral collectors that unsuccessfully explored all northern flank of Pizzo Alzasca (2262 m) at various times and only later realised that these crystals are found at an easily accessible quarry!

The toponym Poncione Alzasca or Poncione d'Alzasca, used in the first reports and no longer in use on the modern maps, is an alternative name for Pizzo Alzasca. The absence of Poncione d'Alzasca on the modern maps and the existence of the very similar toponym Poncione d'Alnasca (although located in a different valley) are the factors that contribute to the misidentification of the real locality for these crystals.

All the best

Paolo

29th Mar 2016 14:34 UTCUwe Kolitsch Manager

Thanks Paolo for the clarification. Will fix this (will take some days).

29th May 2016 19:43 UTCUwe Kolitsch Manager

Now finally done.

Photo http://www.mindat.org/photo-275447.html also transferred.

29th May 2016 20:00 UTCUwe Kolitsch Manager

Also transferred a larger number of very similar photos assigned to "Linescio" and "Pizzo Alzasca" to the Maurino quarry.

1st Jun 2016 14:45 UTCHartmut Hensel Expert

I just noticed that this old thread was followed up in the meantime and issues have been fixed. Thank you Uwe and Paolo for your help. :-)

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