Nut carving, known as Hediao in Chinese, has been an art form in China since the Song period (960 – 1279AD). Olive and peach stones are especially popular but walnuts are also used as raw material. The stones are very hard and very small and it takes strong arms, wrists, and fingers as well as many years of experience to become a good carver. Patience, creative ideas and basic skills in painting are required to make these almost uncanny miniatures. The material is carved with a wide selection of very sharp knives, files and drills and it takes many hours of painstaking work to finish a carving.