Gunpowder was invented by accident when a Daoist alchemist was looking for a way of changing base metals into gold. He mixed together charcoal, sulfur and saltpeter. When they ignited this substance it exploded! Gunpowder was used for festivals for a long time. It was stuffed into hollow sticks of bamboo, ignited and thrown up into the air to make a loud noise. Later in time color was added to the formula for visual effects. Indigo was used to make blue-green, white lead carbonate for white, red lead tetroxide for red, cinnabar for purple and arsenic sulphides for yellow. Powdered cast-iron shavings added bright sparkles. These "fireworks" were launched into the sky to make colorful designs along with loud noises.Firecrackers and fireworks were closely associated with the most important holiday in china- the new year- which begins on the first full moon after January 21st.