A few pieces of bricks, charcoal or coal
1 c. salt
1 c. bluing
Drops of food coloring
1 c. water
4 tbsp. ammonia

Put the small pieces of brick etc., in a shallow pan. Mix the salt water and amonia in a small bowl. Pour over the brick pieces. Add a drop of food coloring here and there on the mixture. Crystals will form and grow to be a colorful garden. Starts to grow in just hours, lasts for weeks.