1/3 c. salt
1/3 c. water
1/3 c. regular laundry bluing
1/3 c. ammonia
3-4 lumps charcoal
Food coloring

Combine water, salt, bluing and ammonia. Place charcoal in a glass dish. Pour mixture over top and dot with a few drops of food coloring. In a few days (when crystal growth stops) action may be re-started by adding a teaspoon of ammonia. NOT EDIBLE.