Shimmering golden crystals of Siderite and Sphalerite after Calcite from a well known, short lived find in South Africa. There are two double terminated crystals on matrix. The Siderite and Sphalerite formed as epimorphs over the Calcite which later dissolved away. Because they are hollow, most are damaged to varying degrees. This is an execellent example in pristine condition. Ex. Tim Sherburn collection.