Siderite, Sphalerite ps. Calcite

Item Description

This is an intergrown pair of the well known scalenohedral epimorphs (complex replacement growths) of Siderite and Sphalerite after Calcite from the Aggenys Mine in South Africa. The crystals are red-brown with satin to matte luster and the original form of the Calcite is preserved very well. The surface of the crystals are somewhat roughly textured, probably upholding the original surface texture of the Calcite, resulting in the satin to matte luster. The piece is also very light as the original Calcite experienced complete dissolution leaving the Siderite-Sphalerite epimorph cast. You can see this in the small, oval hole in the bottom of the specimen that reveals the hollowness of the piece. From a rare, one time find from 20 years ago. Some of these when analysed are more siderite, some more sphalerite - it is an odd mixture!