Siderite and Sphalerite Epimorphs after Calcite

Item Description

A dramatic and excellent miniature specimen from a small find that was brought out at Munich in 2006. These very unusual, barrel-shaped crystals are actually epimorphs, i. e. a 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 cast is hollow. This piece is rare, in that, it is complete all-around and pristine. The back is contacted, but is not broken. Nearly all such piece have some broken areas. One of the best we have seen, in this size. Valued at $150-200. Certainly one of the most unusual calcite pseudomorphs around.