Tennantite ps. Chalcocite - classic pseudomorph

Item Description

For Tsumeb, considered the greatest mine of all, this is a pseudomorph seldom seen in any quality, and is highly desired among collectors. What were once bladed crystals of well-formed Chalcocite have since been transformed into sharp pseudomorphs of black Tennantite with a very attractive green patina. The crystals reach 5.0 cm in length, significant for a Tsumeb pseudo. Pseudomorphs are always interesting in light of the usually complex chemical substitutions at play, and there remains some amount of discussion as to whether the original crystals here were Chalcocite or Azurite, as once thought. Nonetheless, Tennantite pseudos are rare from Tsumeb, and this is a fine one. Formerly in the extensive collection of W & A Cook. These often turn up out of the older Tsumeb collections, leading me to think they came out in the 1950s-60s in some quantity, but are rare now. Pieces like this have been seen at shows in the $1500-2500 price range.