Umangite with Chalcomenite (very rare) (ex Josef Vajdak)

Item Description

An incredibly rare specimen of the copper selenide Umangite from this remote mine in Argentina. The species was first described in 1891. Purplish-black, metallic Umangite grains are scattered between blue crystals of Chalcomenite, an even rarer copper-selenium hydroxide on matrix. This is one of only a handful of pieces of this species that we've seen, and comes with a classic label from Josef Vajdak / Pequa Rare Minerals, which immediately increases the value. You can read Joe's biography here: http://www.minrec.org/labels.asp?colid=1371