I recently bought a set of Brusho crystal colours. You dilute them and make them into paint, or just drop the crystals onto paper and then spray with water, and there are numerous other things you can do.
In the case of this particular one, I had misted a whole sheet of A4 card and it rolled up. I laughed it off and got another piece of card.
Round two. Only misted the middle of the paper this time. I dropped some red and green. I got it nice and wet and then took the other wet card stock and put it on top. When I pulled the cards apart this is what I got. I love it! There will be more.