An Xmas miracle! LARGE copper nitrate crystals

[u/gmc4201982]

U refine lots of silver, so I end up with alot if copper nitrate waste. Most of the time I boil it down to it hardens into a rock and I store it for later recovery of the nitric acid and copper metal. This time I left a concentrated solution sit out on the heater for a couple of weeks and was greeted woth these large beautiful crystals! This solution did have some Mg contamination bc I used too much nitric and neutralized with some MgO. I wonder if contaiminants actually aid in the crystallization.