A really, really odd and remarkably big cobalt calcite floater from this classic Congolese locality, famous for both cobalt and copper minerals. This piece, in particular, comes from a fairly recent find, which I have not found too much information about nor seen too many pieces from, so it probably was a pretty small cavity. Still, this piece is already remarkable just size-wise, as not many cobalt calcites are found to have crystals nowhere near as big, and also, it is just so well crystallized. This specimen is composed of two intergrown, sharp, lustrous, and well-defined rhombohedrons with a deep Bordeaux purple-colored exterior and a colorless normal calcite interior that shows through a few exfoliations found around the piece. This either implies the cobalt-rich exterior represents an external zonation or it is a partial replacement of the surface of the calcite showing through. On this piece's surface, both malachite and heterogenite can be observed, with the malachite being of particular beauty thanks to its striking color contrast.