Siderite and Sphalerite Epimorph after Calcite

Item Description

A dramatic and excellent miniature specimen from a small find that was brought out at Munich in 2006. This very unusual, barrel-shaped crystal is actually an epimorph, i. e. a cast after a calcite crystal, 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, as one partially broken side reveals!