Chalcopyrite, sphalerite-marmatite, quartz and pyrite

One very interesting, strongly weathered, large cabinet-size specimen of black sphalerite-marmatite and quartz, covered by very well-developed chalcopyrite crystals, lately internally corroded and replaced by pyrite.
A perfect specimen of isometric transparent green sphalerite- cleophane crystals, developed on quartz.
Krushev dol mine, Madan, Rhodope mountains, Bulgaria