Cornwall is known for its classic metallic species, among them the oldest "blister coppers" that gave early metallurgists a puzzle when they tried to understand how these "copper balls" form in nature. Blister copper was also an ideal ore source, and in fact nearly all of it was harvested and thrown in the smelters as high grade copper ore, in the heyday of Cornwall. So few good specimens, particularly of this size, have survived. While the earlier history was lost, this came from Tim Sherburn's English collection to Jack through Cal Graeber, sometime back in the 1990s. After a recent cleaning by myself, it sparkles and shines, with a little more brightness, but it still has that classic antique look It has a few spots of what look like very old damage to some spheres here, probably in the pocket in geological time. For the size, and richness, it is a significant specimen.