What is better than a classic, old-time piece of the the very rare copper selenide species Umangite from the Type Locality in Argentina - well seven pieces of course! Documented on its accompanying original late 19th to early 20th century handwritten German label as coming from Sierra di Umanga it is now widely known that the first specimens sent to Germany for analysis in 1889 actually came from a nearby mountain range, Sierra de Cacho, and probably from Las Asperezas mine. Our label still reflects the original locality, simply as that is what is documented on its lovely old label. So, to the specimens. They vary in richness and size, from about 2.5 cm to 1 cm across and richly dispersed with dark grey Umangite appearing to cement brecciated veinstone, to fine disseminations. The greenish-blue alteration on the surface is possibly Chalcomenite but has not been analysed. Ex the superb systematic collection assembled by the brothers Martin and Michael Günther (1951-2007 & 1956-2021) we certainly don't come across this species very often.
