Outstanding specimen of skeletal Galena decorated with Sphalerite from 9th Septemvri mine, Madan ore field, Bulgaria. Very attractive and geometrical arrangement of stacked and aligned Galena overgrowing each other. Excellent parallel growth of cubes and elongated tetragonal prisms on different axes. They grow one atop another forming amazing terraced structure. The skeletal structure is caused by very fast growth of the mineral where the crystal faces do not have the time to be completed because the edges grow faster than the center of the faces.  The faces are strongly matt lustrous. Dark Sphalerite crystals are seen too. Displays attractively on both sides. On the Galena are seen small Quartz crystals proving the natural origin of the skeletal structures. In excellent condition – some minor nicks.
Fabulous specimen from this closed mine – the only one that makes these structures!