This video about a Chinese artist who “paints” with gunpowder (blackpowder) is worth watching.
As usual, when linking to a Vice.com video, I have to point out that a lot of what is said in the video is total nonsense. Gunpowder is not natural, unless anything made from minerals is considered natural (in which case your guns are “natural”). Chinese alchemists started experimenting with methods to refine Potassium Nitrate four hundred years before the medicinal precursor to gunpowder was discovered. It is very unlikely that gunpowder was ever made with naturally occurring and unprocessed Potassium Nitrate.
Thanks to Colin for the link.