A superb example of this most famous of encrustation pseudomorphs, which have been highly desired in the old classics collecting circles since the 1800s. This is one of the sharpest I have seen, with excellent pseudo-triangular symmetry and balance to the shape! These are old classics, seldom seen for sale, and dated to the mid-1800s. They are almost legendary in the historic collecting field, and specimens of these "lady slippers" once sold for way more than their weight in gold back in the day. They are a true oddity, absolutely resembling a "lady's slipper," as the 19th-century English collectors christened these. They are still today the most famous epimorph/pseudomorph one can search for to own. This one has a pleasing chocolate brown color (some are rather grey), and is an extremely sharp cast of what once was a bladed crystal of Baryte, replaced by encrustation by the siderite. Long in the noted pseudomorphs collection of Dr Wouter van Tichelen of Brussels.