Yesterday I've made an experiment with lead acetate and zinc. If you put metalic zinc in lead acetate solution, metalic lead and zinc acetate are formed. In these conditions lead will have shape of bubbles. But if you mix lead acetate solution with agar solution and put zinc in it, you will see beautiful lead crystals coming around zinc trough agar gel.
This is what happened after one hour when zinc was added.
After five hours.
And after a day.
And crystals are still growing...