In the morning, with the forge *cough* chiminea *cough* set up, charcoal and blowpipe at the ready, I set up a small pile of lump charcoal, inserted the cone with some of the dust, and lit the coals. Using the blowpipe took a little practice, and I couldn't keep a 100% duty cycle for the hour-plus it took for the charcoal to burn down, but it did seem to make a difference. Still before noon, the charcoal had burned away, and left ash and assorted rubbish in the bottom of the chiminea. The cone had tipped a bit, so I wasn't too shocked when it didn't contain a little lump of copper at the bottom. I carefully shoveled out all the ash, and started sifting through it. The problem was, I didn't really know what I was looking for: I expected to find a little solidified button or puddle of copper, either on the bottom of the forge or in the cone. Nope. Clearly I was a more powerful alchemist than I had realized: I had caused the substance to disappear entirely! :)
I assumed that the copper had done one of two things: broken down into prills so small I didn't recognize them, or literally floated away in the breeze as either vapor or very hot micro-prills. Nevertheless, I set aside all the ash from the bottom of the forge and kept it for later.