“This is mostly a single, very large crystal of galena. It is difficult to pin-point which mine in the Madan ore field produced any particular specimen of galena, but the Borieva mine is well-known for supplying very large, mirror-like crystals such as this one. The apparent six-sided faces are modified octahedral faces, and the square faces are remnants of cubic faces (octahedrons modified by dodecahedrons also produce square faces, but those squares are oriented differently with respect to each other). Norman King collection, photograph, and crystallography.”