[3chelon]

When I was a school kid, a friend and I were into blowing stuff up and general chemical mayhem (those innocent pre-9/11 days!). We used to synthesize fuming nitric acid and mix it with oleum and potassium permanganate. The resulting fuming, purple mix would cause pretty much anything it came into contact with to immediately combust.

But that sounds - if you'll pardon the pun - like child's play compared to your boiling(!) nitric, HF and perchloric acid. I cannot image how you'd even contain such an evil substance? And what was it used for?

[julian_t]

We mixed it fresh every day, and to contain it we used crucibles made from a platinum/gold alloy. Which, needless to say, were locked away very carefully at the end of the day.

And I was using it to dissolve up rock specimens for analysis: basaltic lavas that contained chromite and other notably insoluble minerals.

That stuff would dissolve anything...