This specimen from Kaiwu is really distinctive (and really hard to photograph). It is comprised almost entirely of bright sharp chalcopyrite crystals, the largest of which is 3.5 cm. Some of the chalcopyrites are quite complex in growth.  I'm really not one to lie around and attribute shapes to clouds -  or minerals - but the large chalcopyrite really looks like a mountain. The chalcopyrites are dusted with epitactic sphalerite, giving them a cool silvery-black sheen at certain angles, and the nests of siderite crystals really complete the piece. There is no damage from the front viewing angle (a small chip in the large crystal is visible if oriented in the reverse). Great specimen.