Coal flowers aren't actually flowers, but a craft that has historically been practiced by coal-mining families since the late 1800s. Because coal was plentiful but money wasn't, coal flowers became a favored household decoration, especially around the winter holidays. Although the craft has fallen out of favor in recent years, it's still an interesting craft, an effective science lesson and a good opportunity for kids to discuss cultural traditions.
Arrange several lumps of coal in a pie plate or a shallow bowl. Decorate the coal with different items, such as fabric scraps, yarn, twigs or pine cones, then secure them with a bit of glue.
Combine the table salt, water, household ammonia and bluing in a small bowl. Add few drops of food coloring if you like. Pour the mixture slowly over the coal arrangement.
Put the plate in a safe place where it won't be bumped or jostled.
Watch for the crystals to begin forming, which should occur in just a few hours, depending on the temperature. Within 24 hours, the coal and decorations should be covered with crystal "flowers."