Spark rocks

These tools used by Earth Kingdom citizens to start fires are mined from cliffs found south of Ba Sing Se, known as the Fighting Cliffs. The cliffs, one white and one red, face each other with a wide ravine between them, and early Earth Kingdom peoples noticed that the ground of the ravine was charred and black. Legend says that the cliffs were created in an ancient battle between Earthbenders and Firebenders, and that the conflict was so awesome that the very ground they fought on soaked up their power and animosity.