Umangite, Clausthalite, & Friends
Sierra de Cacheuta, Mendoza, Argentina
Miniature, 3.5 x 3.1 x 1.4 cm
Ex. Philadelphia Academy of Natural Sciences
A slightly less rich example than the above specimen, but clearly collected at the same time and in fact with the same number painted upon them. There is a lot more than clausthalite in here! I am told that if you have purple (and you do, visible, here!), you have umangite; and its a good bet there is klockmannite as well, and potentially all kinds of other good things. This specimen also contains Copper selenides because of the green secondaries. The non-metallic blue on there is likely chalcomenite, in fact. These specimens were presented to the academy by Casimiro Domeyko, who did much work on the rare minerals of Chile and Argentina. This specimen has more silvery metallic material running along one face, a color seemingly absent in the specimen below. Note these are for sale "as is" with the ID as "Clausthalite and friends"...I have not analyzed them.