This style of combination, with chalcopyrite covering sharp calcite crystals, is destined to become an iconic example of Chinese minerals from this century. In 2015, a startling new find of calcite coated by chalcopyrite emerged at the Shanghai mineral show, and I purchased as many as I could get my hands on over the following few years. The individual crystals are sub-1mm, and the coating on calcite creates an undulating, glittering carpet of scintillating sparkle. A HUGE main crystal dominates the piece, at 7.2 cm long/tall, and it's twinned, too! We buy these back, every chance we get, as no more have come out since. The few that had this rich, even coverage without damage - those were always rare and this is one of the best in size class. We should know, as we bought and exported nearly all the great ones at the time.