A very nice specimen with copper pseudomorphs of river worn pebbles from the famous conglomerate-hosted copper deposits of Michigan. These kinds of specimens form from the wholesale replacement of pebbles and fine-grained matrix material within porous, conglomeratic sedimentary beds that once acted as conduits for Cu-rich brines. This piece features several well rounded copper pseudos stacked in a delicate array on top of a larger mass of copper that likely filled interstitial space within the conglomerate. This piece has two old collection numbers on its back side, and comes with the full label from the Henderson Collection. A truly unique specimen for the collector of natural curios.