A very fine, white powder, this is the stuff of late night exam crams and early mornings. This powder sublimates at a very low temperature. When it is heated in a test tube with a smaller test tube inserted inside, the powder turns to a gas, rises, and then sublimates back into a thin, solid crystal on the bottom of the second test tube. The resulting crystals are very delicate and resemble frost patterns on window panes.
LL Demos & Lab: Caffeine Cathedrals