The selenides included mainly the nickel selenide penroseite, intimately mixed with selenides of lead (clausthalite), silver (naumannite) and mercury (tiemannite).
Assays have shown the selenides from the West Vein to be dominated by penroseite and to include clausthalite, tiemannite and naumannite with possible krutaite (although the Cu may be chalcopyrite).
Scalenohedral calcite crystals were observed in vugs on top of penroseite and with clausthalite and chalcopyrite associated with overgrowths of tellurates (?) (C.
In polished section it is seen to grow on top of clausthalite (C.
Clausthalite was first identified from Pacajake by Block and Ahlfeld (1937).
Originally described from Cacheuta in Argentina by Bertrand (1882), molybdomenite is very rare at Pakajake, where it occurs as an oxidation product of clausthalite. It was identified at Pacajake by Herzenberg, who described it as occurring in white tabular crystals which gave lead and selenium by the blowpipe test, and which could be the same as the molybdomenite from Cacheuta (Block and Ahlfeld, 1937).
Block and Ahlfeld (1937) repeated this description, and Ahlfeld (1941) described it as small, colorless crystals with a brilliant luster in small geodes coating clausthalite and limonite.
Associated minerals are: chrisstanleyite, tiemannite, clausthalite, stibiopalladinite, gold, ankerite and calcite.
Hardness: could not be determined because of complex intergrowth with other minerals, but it has a polishing hardness similar to that of chrisstanleyite, greater than that of tiemannite and clausthalite, but lower than that of stibiopalladinite.
Associated minerals are: pascoite, sherwoodite, selenium, bariandite, devilline, rossite, hewettite, carnotite, clausthalite
, coffinite, tyuyamunite, uraninite, corvusite, montroseite, roscoelite, galena, pyrite and tennantite.
was reported from the Bor pit by Lisitsyn and Malinko (1994).
Specimens of another rare selenium mineral, poubaite (with clausthalite
) were also available from the same locality.