A superb example of the rare Siderite pseudomorph after Baryte 'Lady's Slipper' from the one and only location for this classic Devonshire curiosity. The Slipper specimens from the Virtous Lady Mine and the fabled Siderite 'Boxes' were found in 1832-33. This particular 'Lady's Slipper' is over 9cm long, the Siderite forming a sheath-like casing of intergrown lenticular (fish scale) crystals. The colour varies from translucent light yellow-brown to brown. The Siderite is lightly sprinkled with minute crystals of sparkling golden metallic Pyrite. An extremely fine example of a rare specimen, with superb equant form.