I'm not sure what size copper nuggets usually come in, but this has to be on the upper end of the bigness scale. Those white bits you can see caught up in its formation are chunks of quartz, though without this knowledge I'd have guessed "extra-terrestrial copper-eating fungus".
Click on the image for a larger version.
According to the Reddit thread it features in, the image was taken by a geologist with the handle "GeoRhi".
"Yes I (lady geologist) unearthed this copper nugget, with it's quartz core last month. Not a international or national event but I was the first person ever to see this. So I think it's pretty cool."
Count me in — I reckon it's magnificent.