This is a robust, complete-all-around crystal of wulfenite that has been totally replaced by duftite, a unique occurrence found only at Tsumeb in good specimens. And there, it is still rare. I have seen numerous small, flimsy examples, but this is a robust crystal, nearly 2 cm across and very thick (several mm). It is on a beautiful rolling matrix of duftite and replaced wulfenite. Large thumbnail or toenail sized specimen, ex Desmond Sacco Thumbnail Collection