Siderite and Sphalerite ps. Calcite - Broken Hill Mine, Aggeneys, Namakwa Dist. Mun., Northern Cape, South Africa More info: https://www.irocks.com/minerals/specimen/53190 From a relatively small find in 2006 from the Broken Hill Mine (misleadingly labeled as the Aggeneys Mine when they were first brought out) in South Africa, these unusual crystals are actually hollow casts after calcite that are epimorphic shells comprised of a mixture of mixture of siderite and sphalerite (some spots are more