Around 15-16 years ago, there was a massive discovery of world class cuprite crystals at the Rubtsovskoe Mine--they were a staple of the Russian dealers for a few years after the find-- though a couple years after the initial discovery of those more ubiquitous cuprite crystals, these really interesting copper pseudomorphs after cuprite were discovered, though they came out in much smaller numbers than the cuprites. 

This one hosts a couple large octahedral pseuodos, the larger one a hopped octahedron approximately 2.6 cm on the diagonal, sitting on a mass of copper crystals, with just a little cuprite still remaining here and there.