Potassium bitartrate is also a great introduction to crystals. Get a bottle of good red wine, 2010 or thereabouts. Uncork and drink it. Now look at the bottom

Potassium bitartrate is also a great introduction to crystals. Get a bottle of good red wine, 2010 or thereabouts. Uncork and drink it. Now look at the bottom of the last glass, if you still can, and - voila - potassium bitartrate. If you don't find any, don't despair and try another bottle.