Superb Siderite and Sphalerite ps. After Calcite

Item Description

A superb specimen from a small find that was brought out at Munich in 2006. It is one of the very few pieces, that were complete all-around and pristine! These very unusual, barrel-shaped crystals are actually epimorphs, i. e. casts after calcite crystals, which have been dissolved away. Microprobe analysis in South Africa by Bruce Cairncross and others shows that the shimmering, metallic-like coating is a mixture of siderite and sphalerite. The piece is very light weight for its size and, in fact, the casts are hollow, as other damaged pieces we have handled reveal. An interesting, totally unique find!