Siderite and Sphalerite Epimorphs after Calcite

Item Description

These Aggeneys calcite epimorphs are certainly some of the most unusual and facinating pseudomorphs around. This dramatic and showy small cabinet is 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, as the striking broken faces reveal. The composition, including the broken faces really add to the interest of this 360-degree specimen.