4 tbsp. salt
4 tbsp. water
4 tbsp. laundry bluing
1 tbsp. ammonia
Few drops mercurochrome or food coloring
Pieces of coal or brick

Pour this mixture over some pieces of brick or coal in an old saucer. With a medicine dropper, sprinkle with a few drops of mercurochrome or food coloring over the mixture. In a few hours tiny crystal will begin to form. They will grow for a few days.