Introduction to refined coal products: Refined coal products are mainly produced in Fushun, Liaoning Province. They are black and shiny, crystal clear and lovely, and are harder than coal, delicate and free of impurities. It was only in modern times that they were used for carvings. These 7,200-year-old coal-carving artworks show the uniqueness of the Xinle people who are good at inventing and using local materials.